One day little Vasya found mom's pocket book. The book had n names of her friends and unusually enough, each name was exactly m letters long. Let's number the names from 1 to n in the order in which they are written.

As mom wasn't home, Vasya decided to play with names: he chose three integers i, j, k (1 ≤ i < j ≤ n, 1 ≤ k ≤ m), then he took names number i and j and swapped their prefixes of length k. For example, if we take names "CBDAD" and "AABRD" and swap their prefixes with the length of 3, the result will be names "AABAD" and "CBDRD".

You wonder how many different names Vasya can write instead of name number 1, if Vasya is allowed to perform any number of the described actions. As Vasya performs each action, he chooses numbers i, j, k independently from the previous moves and his choice is based entirely on his will. The sought number can be very large, so you should only find it modulo 1000000007 (109 + 7).

Input

The first input line contains two integers n and m (1 ≤ n, m ≤ 100) — the number of names and the length of each name, correspondingly. Then n lines contain names, each name consists of exactly m uppercase Latin letters.

Output

Print the single number — the number of different names that could end up in position number 1 in the pocket book after the applying the procedures described above. Print the number modulo 1000000007 (109 + 7).

Examples

Input

2 3
AAB
BAA


Output

4


Input

4 5
ABABA
BCGDG
AAAAA
YABSA


Output

216

Note

In the first sample Vasya can get the following names in the position number 1: "AAB", "AAA", "BAA" and "BAB".


/*
		     * Author- Kishan_25
		     * BTech 2nd Year DAIICT
		     */
		     
		            
		    import java.io.*;
		    import java.math.*;
		    import java.util.*;
		 
		    public class TR {
		    	private static InputStream stream;
		    	private static byte[] buf = new byte[1024];
		    	private static int curChar;
		    	private static int numChars;
		    	private static SpaceCharFilter filter;
		    	private static PrintWriter pw;
		    	private static long count = 0,mod=1000000007;
		    	private static TreeSet<Integer>ts[]=new TreeSet[200000];
		    	private static HashSet hs=new HashSet();
		     
		    	public static void main(String[] args) {
		    		InputReader(System.in);
		    		pw = new PrintWriter(System.out); 
		    		new Thread(null ,new Runnable(){
		    		public void run(){
		    		try{
		    		soln();//This is solution method
		    		pw.close();
		    		} catch(Exception e){
		    		e.printStackTrace();
		    		}
		    		}
		    		},"1",1<<26).start();
		    		}
		    	
		    
		    	public static long gcd(long x, long y) {
		    		if (x == 0)
		    			return y;
		    		else
		    			return gcd( y % x,x);
		    	}
		    	
		    	private static int BinarySearch(int a[], int low, int high, int target) {
		    		if (low > high)
		    			return -1;
		    		int mid = low + (high - low) / 2;
		    		if (a[mid] == target)
		    			return mid;
		    		if (a[mid] > target)
		    			high = mid - 1;
		    		if (a[mid] < target)
		    			low = mid + 1;
		    		return BinarySearch(a, low, high, target);
		    	}
		    	
		    	public static String reverseString(String s) {
		    		StringBuilder sb = new StringBuilder(s);
		    		sb.reverse();
		    		return (sb.toString());
		    	}
		    	
		    	public static long pow(long n, long p) {
		    		if(p==0)
		    			return 1;
		    		if(p==1)
		    			return n%mod;
		    		if(p%2==0){
		    			long temp=pow(n, p/2);
		    		return (temp*temp)%mod;
		    		}else{
		    			 	long temp=pow(n,p/2);
		    			 	temp=(temp*temp)%mod;
		    			 	return(temp*n)%mod;
		    			 	
		    		}
		    	}
		     
		    		
		     
		    	public static int[] radixSort(int[] f) {
		    		int[] to = new int[f.length];
		    		{
		    			int[] b = new int[65537];
		    			for (int i = 0; i < f.length; i++)
		    				b[1 + (f[i] & 0xffff)]++;
		    			for (int i = 1; i <= 65536; i++)
		    				b[i] += b[i - 1];
		    			for (int i = 0; i < f.length; i++)
		    				to[b[f[i] & 0xffff]++] = f[i];
		    			int[] d = f;
		    			f = to;
		    			to = d;
		    		}
		    		{
		    			int[] b = new int[65537];
		    			for (int i = 0; i < f.length; i++)
		    				b[1 + (f[i] >>> 16)]++;
		    			for (int i = 1; i <= 65536; i++)
		    				b[i] += b[i - 1];
		    			for (int i = 0; i < f.length; i++)
		    				to[b[f[i] >>> 16]++] = f[i];
		    			int[] d = f;
		    			f = to;
		    			to = d;
		    		}
		    		return f;
		    	}
		     
		    	public static int nextPowerOf2(final int a) {
		    		int b = 1;
		    		while (b < a) {
		    			b = b << 1;
		    		}
		    		return b;
		    	}
		     
		    	public static boolean PointInTriangle(int p1, int p2, int p3, int p4, int p5, int p6, int p7, int p8) {
		    		int s = p2 * p5 - p1 * p6 + (p6 - p2) * p7 + (p1 - p5) * p8;
		    		int t = p1 * p4 - p2 * p3 + (p2 - p4) * p7 + (p3 - p1) * p8;
		     
		    		if ((s < 0) != (t < 0))
		    			return false;
		     
		    		int A = -p4 * p5 + p2 * (p5 - p3) + p1 * (p4 - p6) + p3 * p6;
		    		if (A < 0.0) {
		    			s = -s;
		    			t = -t;
		    			A = -A;
		    		}
		    		return s > 0 && t > 0 && (s + t) <= A;
		    	}
		     
		    	public static float area(int x1, int y1, int x2, int y2, int x3, int y3) {
		    		return (float) Math.abs((x1 * (y2 - y3) + x2 * (y3 - y1) + x3 * (y1 - y2)) / 2.0);
		    	}
		     
		    	public static boolean isPrime(int n) {
		    		// Corner cases
		    		if (n <= 1)
		    			return false;
		    		if (n <= 3)
		    			return true;
		     
		    		// This is checked so that we can skip 
		    		// middle five numbers in below loop
		    		if (n % 2 == 0 || n % 3 == 0)
		    			return false;
		     
		    		for (int i = 5; i * i <= n; i = i + 6)
		    			if (n % i == 0 || n % (i + 2) == 0)
		    				return false;
		     
		    		return true;
		    	}
		     
		    	//merge Sort
		     
		    	static long sort1(int a[])
		    	{  int n=a.length;
		    		int b[]=new int[n];	
		    		return mergeSort(a,b,0,n-1);}
		    	static long mergeSort(int a[],int b[],long left,long right)
		    	{ long c=0;if(left<right)
		    	 {   long mid=left+(right-left)/2;
		    		 c= mergeSort(a,b,left,mid);
		    		 c+=mergeSort(a,b,mid+1,right);
		    		 c+=merge(a,b,left,mid+1,right); }	
		    		return c;	 }
		    	static long merge(int a[],int  b[],long left,long mid,long right)
		    	{long c=0;int i=(int)left;int j=(int)mid; int k=(int)left;
		    	while(i<=(int)mid-1&&j<=(int)right)
		    	{ if(a[i]>a[j]) {b[k++]=a[i++]; }
		    	else	{ b[k++]=a[j++];c+=mid-i;}}
		    	while (i <= (int)mid - 1)   b[k++] = a[i++]; 
		    	while (j <= (int)right) b[k++] = a[j++];
		    	for (i=(int)left; i <= (int)right; i++) 
		    		a[i] = b[i];  return c;  }
		    	public static boolean isSubSequence(String large, String small, int largeLen, int smallLen) {
		    		//base cases
		    		if (largeLen == 0)
		    			return false;
		    		if (smallLen == 0)
		    			return true;
		    		// If last characters of two strings are matching
		    		if (large.charAt(largeLen - 1) == small.charAt(smallLen - 1))
		    			isSubSequence(large, small, largeLen - 1, smallLen - 1);
		    		// If last characters are not matching
		    		return isSubSequence(large, small, largeLen - 1, smallLen);
		    	}
		     
		    	// To Get Input
		    	// Some Buffer Methods
		     
		    	public static void InputReader(InputStream stream1) {
		    		stream = stream1;
		    	}
		     
		    	private static boolean isWhitespace(int c) {
		    		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		    	}
		     
		    	private static boolean isEndOfLine(int c) {
		    		return c == '\n' || c == '\r' || c == -1;
		    	}
		     
		    	private static int read() {
		    		if (numChars == -1)
		    			throw new InputMismatchException();
		    		if (curChar >= numChars) {
		    			curChar = 0;
		    			try {
		    				numChars = stream.read(buf);
		    			} catch (IOException e) {
		    				throw new InputMismatchException();
		    			}
		    			if (numChars <= 0)
		    				return -1;
		    		}
		    		return buf[curChar++];
		    	}
		     
		    	private static int nextInt() {
		    		int c = read();
		    		while (isSpaceChar(c))
		    			c = read();
		    		int sgn = 1;
		    		if (c == '-') {
		    			sgn = -1;
		    			c = read();
		    		}
		    		int res = 0;
		    		do {
		    			if (c < '0' || c > '9')
		    				throw new InputMismatchException();
		    			res *= 10;
		    			res += c - '0';
		    			c = read();
		    		} while (!isSpaceChar(c));
		    		return res * sgn;
		    	}
		     
		    	private static long nextLong() {
		    		int c = read();
		    		while (isSpaceChar(c))
		    			c = read();
		    		int sgn = 1;
		    		if (c == '-') {
		    			sgn = -1;
		    			c = read();
		    		}
		    		long res = 0;
		    		do {
		    			if (c < '0' || c > '9')
		    				throw new InputMismatchException();
		    			res *= 10;
		    			res += c - '0';
		    			c = read();
		    		} while (!isSpaceChar(c));
		    		return res * sgn;
		    	}
		     
		    	private static String nextToken() {
		    		int c = read();
		    		while (isSpaceChar(c))
		    			c = read();
		    		StringBuilder res = new StringBuilder();
		    		do {
		    			res.appendCodePoint(c);
		    			c = read();
		    		} while (!isSpaceChar(c));
		    		return res.toString();
		    	}
		     
		    	private static String nextLine() {
		    		int c = read();
		    		while (isSpaceChar(c))
		    			c = read();
		    		StringBuilder res = new StringBuilder();
		    		do {
		    			res.appendCodePoint(c);
		    			c = read();
		    		} while (!isEndOfLine(c));
		    		return res.toString();
		    	}
		     
		    	private static int[] nextIntArray(int n) {
		    		int[] arr = new int[n];
		    		for (int i = 0; i < n; i++) {
		    			arr[i] = nextInt();
		    		}
		    		return arr;
		    	}
		     
		    	private static int[][] next2dArray(int n, int m) {
		    		int[][] arr = new int[n][m];
		    		for (int i = 0; i < n; i++) {
		    			for (int j = 0; j < m; j++) {
		    				arr[i][j] = nextInt();
		    			}
		    		}
		    		return arr;
		    	}
		    	private static char[][] nextCharArray(int n,int m){
		    		char [][]c=new char[n][m];
		    		for(int i=0;i<n;i++){
		    			String s=nextLine();
		    			for(int j=0;j<s.length();j++){
		    				c[i][j]=s.charAt(j);
		    			}
		    		}
		    		return c;
		    	}
		     
		    	private static long[] nextLongArray(int n) {
		    		long[] arr = new long[n];
		    		for (int i = 0; i < n; i++) {
		    			arr[i] = nextLong();
		    		}
		    		return arr;
		    	}
		     
		    	private static void pArray(int[] arr) {
		    		for (int i = 0; i < arr.length; i++) {
		    			pw.print(arr[i] + " ");
		    		}
		    		pw.println();
		    		return;
		    	}
		     
		    	private static void pArray(long[] arr) {
		    		for (int i = 0; i < arr.length; i++) {
		    			pw.print(arr[i] + " ");
		    		}
		    		pw.println();
		    		return;
		    	}
		     
		    
		     
		    	private static boolean isSpaceChar(int c) {
		    		if (filter != null)
		    			return filter.isSpaceChar(c);
		    		return isWhitespace(c);
		    	}
		     
		    	private interface SpaceCharFilter {
		    		public boolean isSpaceChar(int ch);
		    	}
		     
		   
		    	//----------------------------------------My Code------------------------------------------------//
		
	 
		    
				private static void soln() {
		    	
					
					Scanner in = new Scanner(System.in);
					
					int n = in.nextInt();
					int m = in.nextInt();
					in.nextLine();
					
					char[][] arr = new char[n][m];
					
					for(int i = 0;i<n;i++){
						String l = in.nextLine();
						
						for(int j = 0;j<m;j++){
							arr[i][j] = l.charAt(j);
						}
					}
					
					
					long ans = 1;
					
					for(int i = 0;i<m;i++){
						boolean temp[] = new boolean[26];
						
						for(int j = 0;j<n;j++){
							int a = arr[j][i] -'A';
							temp[a] = true;
						}
						
						int k = 0;
						
						for(int j = 0;j<26;j++){
							if(temp[j]){
								k++;
							}
						}
						k%= 1000000007;
						
						ans = (ans*k)%1000000007;
					}
					
					System.out.println(ans);
		    	}//-----------------------------------------The End--------------------------------------------------------------------------//

				
				public static boolean[] call(){
					 boolean prime[] = new boolean[7368788];
					  Arrays.fill(prime, true);
					 
					    for (int p=2; p*p<=500000; p++)
					    {
					        // If prime[p] is not changed, then it is a prime
					        if (prime[p] == true)
					        {
					            // Update all multiples of p
					            for (int i=p*2; i<=7368787; i += p)
					                prime[i] = false;
					        }
					    }
					    
					    return prime;
				}
				
		    	
		    	
		    	public static BigInteger min(BigInteger a,BigInteger b){
		    		if(a.compareTo(b) == -1){
		    			return a;
		    		}else{
		    			return b;
		    		}
		    	}
		    	
		    	public static BigInteger max(BigInteger a,BigInteger b){
		    		if(a.compareTo(b) == -1){
		    			return b;
		    		}else{
		    			return a;
		    		}
		    	}
		    	 public static int toDecimal(String str) {
		    		    int decimal = 0;
		    		    int base0 = (int)'0';
		    		    char ch;
		    		    for (int i = 0; i < str.length(); i++) {
		    		      ch = str.charAt(i);
		    		      if (charIsNotBinary(ch)) {
		    		        return 0;
		    		      }
		    		      decimal = decimal * 2 + ((int)str.charAt(i) - base0);
		    		    }
		    		    return decimal;
		    		  }
		    	 
		    	 private static boolean charIsNotBinary(char ch) {
		    		    return '1' < ch || ch < '0';
		    		  }
		    	 
		    	 
		    	 // union code starts
		    	 
		    	 private static void initialize( int Arr[ ],int size[], int N)
		    	    {
		    	        for(int i = 0;i<N;i++)
		    	        {
		    	        	Arr[ i ] = i ;
		    	        	size[ i ] = 1;
		    	        }
		    	    }
		    	 
		    	 private static int root(int Arr[ ],int i)
		    	    {
		    	        while(Arr[ i ] != i)           //chase parent of current element until it reaches root
		    	        {
		    	            Arr[ i ] = Arr[ Arr[ i ] ] ; 
		    	            i = Arr[ i ];
		    	        }
		    	        return i;
		    	    }
		    	 
		    	 private static void union(int Arr[ ],int size[ ],int A,int B)
		    	    {
		    	        int root_A = root(Arr,A);
		    	        int root_B = root(Arr,B);
		    	        if(size[root_A] < size[root_B ])
		    	        {
		    	    Arr[ root_A ] = Arr[root_B];
		    	    size[root_B] += size[root_A];
		    	    }
		    	        else
		    	        {
		    	    Arr[ root_B ] = Arr[root_A];
		    	    size[root_A] += size[root_B];
		    	    }

		    	    }
		    	 
		    	 private static boolean find(int Arr[],int A,int B)
		    	    {
		    	        if( root(Arr,A)==root(Arr,B) )       //if A and B have the same root, it means that they are connected.
		    	        return true;
		    	        else
		    	        return false;
		    	    }
		    	 
		    	 
		    	 // union code ends
		 }
		   
		    class TrieNode {
		        TrieNode[] arr;
		        boolean isEnd;
		        // Initialize your data structure here.
		        public TrieNode() {
		            this.arr = new TrieNode[26];
		        }
		     
		    }
		     
		     class Trie {
		        private TrieNode root;
		     
		        public Trie() {
		            root = new TrieNode();
		        }
		     
		        // Inserts a word into the trie.
		        public void insert(String word) {
		            TrieNode p = root;
		            for(int i=0; i<word.length(); i++){
		                char c = word.charAt(i);
		                int index = c-'a';
		                if(p.arr[index]==null){
		                    TrieNode temp = new TrieNode();
		                    p.arr[index]=temp;
		                    p = temp;
		                }else{
		                    p=p.arr[index];
		                }
		            }
		            p.isEnd=true;
		        }
		     
		        // Returns if the word is in the trie.
		        public boolean search(String word) {
		            TrieNode p = searchNode(word);
		            if(p==null){
		                return false;
		            }else{
		                if(p.isEnd)
		                    return true;
		            }
		     
		            return false;
		        }
		     
		        // Returns if there is any word in the trie
		        // that starts with the given prefix.
		        public boolean startsWith(String prefix) {
		            TrieNode p = searchNode(prefix);
		            if(p==null){
		                return false;
		            }else{
		                return true;
		            }
		        }
		     
		        public TrieNode searchNode(String s){
		            TrieNode p = root;
		            for(int i=0; i<s.length(); i++){
		                char c= s.charAt(i);
		                int index = c-'a';
		                if(p.arr[index]!=null){
		                    p = p.arr[index];
		                }else{
		                    return null;
		                }
		            }
		     
		            if(p==root)
		                return null;
		     
		            return p;
		        }
		    }	
		    	
		    
		    
			class Pair implements Comparable<Pair>{
			    long id; 
				long w;
				long h;
				Pair(long id,long w,long h){
					this.id=id;
					this.w=w;
					this.h=h;
				}
				@Override
				public int compareTo(Pair o) {
					// TODO Auto-generated method stub
				//	Sort in increasing order
	 
					if(w>o.w)
						return 1;
					else if(w<o.w)
						return -1;
					else{
						if(h>o.h){
							return 1;
						}else if(o.h>h)
							return -1;
						else return 0;
					}
					
				}
			
			}
		        class Graph{
		        	private static int V,level[][],count=-1,lev_dfs[],degree=0,no_vert_conn_comp=0;
		        	private Stack <Integer>st=new Stack();
		        	private static LinkedList<Integer > adj[];
		        	private boolean[][] Visite;
		        	private static boolean [] Visited;
		        	private static TreeSet<Integer> ts=new TreeSet();
		    Graph(int V){
		    V++;
		    this.V=(V);
		    adj=new LinkedList[V];
		    Visite=new boolean[100][100];
		    
	 	   Visited=new boolean[V];
		 
	 	   
	 	   level=new int[100][100];
		   lev_dfs=new int[V]; 
		   for(int i=0;i<V;i++)
			   adj[i]=new LinkedList<Integer>();
		    }
		     
		    void addEdge(int v,int w){
		    	
		    	if(adj[v]==null){
		    		adj[v]=new LinkedList();
		    	}
		    	if(adj[w] == null){
		    		adj[w] = new LinkedList();
		    	}
		    	adj[v].add(w);
		    
		    	
		    }
		    
		    
		    public static void conCop(int startVert){
		    	Visited=new boolean[V];
		    	int totalcon = 1;
		    	Queue<Integer> q=new LinkedList<Integer>();
		    	q.add(startVert);
		    	Visited[startVert] = true;
		    	
		    	while(!q.isEmpty()){
		    		int top=q.poll();
		    		
		    		Iterator<Integer> i= adj[top].listIterator();
		    		while(i.hasNext()){
		    			int n=i.next();
		    			if(!Visited[n]){
		    				q.add(n);
		    				Visited[n]=true;
		    				totalcon++;	    			
		    			}
		    		}
		    	}
		    	q.clear();
		    	
		    	
		    }
		    
		 
		    public static int BFS2(int startVert){
		    	
		    	for(int i=0;i<V;i++){
		    		lev_dfs[i]=-1;
		    	}
		    	Queue<Integer> q=new LinkedList<Integer>();
		    	q.add(startVert);
		    	
		    	lev_dfs[startVert]=0;
		    	while(!q.isEmpty()){
		    		int top=q.poll();
		    		
		    		Iterator<Integer> i= adj[top].listIterator();
		    		while(i.hasNext()){
		    			int n=i.next();
		    			if(!Visited[n]){
		    				q.add(n);
		    				Visited[n]=true;
		    				lev_dfs[n]=lev_dfs[top]+1;
		    				//System.out.println(top + " " + n);
		    			}
		    		}
		    	}
		    	q.clear();
		    	
		    	int mx = 0;
		    	for(int i = 0;i<V;i++){
		    		mx = Math.max(mx, lev_dfs[i]);
		    	}
		    	return mx;
		    }
		    
		  
		    public int getEd(){
		    	return degree/2;
		    }
		    
		    public void get(int from,int to){
		    	int h=lev_dfs[from]-lev_dfs[to];
		    	if(h<=0){
		    		System.out.println(-1);
		    	}else{
		    		System.out.println(h-1);
		    	}
		    }
		  
		
		     public long dfs(int startVertex){
	   	 
	    	 if(!Visited[startVertex])  {		    
		   return dfsUtil(startVertex,Visited);	    	
		    	}	      
		    	 return 0;
		    	}
		 private long dfsUtil(int startVertex, boolean[] Visited) {//0-Blue 1-Pink
		 
			 int c=1;
			 long cout=0;
		      degree=0;
		    	Visited[startVertex]=true;
		    	lev_dfs[startVertex]=1;
		      st.push(startVertex);
		    while(!st.isEmpty()){
		    	
		    	int top=st.pop();
		    int child=adj[top].size();
		    if(top!=startVertex)
		    	child--;
		    
		    	ts.add(top);
		    	Iterator<Integer> i=adj[top].listIterator();
		     degree+=adj[top].size();
		     
		    while(i.hasNext()){
		    
		    	int n=i.next();
		     if( !Visited[n]){
		    				Visited[n]=true;
		    					st.push(n);
		    					if(adj[n].size()-1>child)
		    					cout++;	
		    				c++;
		    					lev_dfs[n]=lev_dfs[top]+1;
		    			
		    		 }
		         }
		 }
		    return cout;
		    	
    
		    }
		        
		        }     
		        	
		        
		    
		    
		 
		    class Heap{
		    	
		    	public static void build_max_heap(long []a,int size){
		    		
		    		for(int i=size/2;i>0;i--){
		    			max_heapify(a, i,size);
		    		}
		    		
		    			}
		    	private static void max_heapify(long[] a,int i,int size){
		    		int left_child=2*i;
		    		int right_child=(2*i+1);
		    		int largest=0;
		    		
		    		if(left_child<size && a[left_child]>a[i]){
		    			largest=left_child;
		    		}else{
		    			largest=i;
		    		}
		    		
		    		if(right_child<size && a[right_child]>a[largest]){
		    			largest=right_child;
		    		}
		    		if(largest!=i){
		    			long temp=a[largest];
		    			a[largest]=a[i];
		    			a[i]=temp;
		    			max_heapify(a, largest,size);
		    		}
		    	}
		    	private static void min_heapify(int[] a,int i){
		    		int left_child=2*i;
		    		int right_child=(2*i+1);
		    		int largest=0;
		    		
		    		if(left_child<a.length && a[left_child]<a[i]){
		    			largest=left_child;
		    		}else{
		    			largest=i;
		    		}
		    		
		    		if(right_child<a.length && a[right_child]<a[largest]){
		    			largest=right_child;
		    		}
		    		if(largest!=i){
		    			int temp=a[largest];
		    			a[largest]=a[i];
		    			a[i]=temp;
		    			min_heapify(a, largest);
		    		}
		    	}
		    	public static void extract_max(int size,long a[]){
		    		if(a.length>1){
		    			long max=a[1];
		    			a[1]=a[a.length-1];
		    			size--;
		    			max_heapify(a, 1,a.length-1);
		    		}
		    	}
		    }
		    
		    class Node{
		    	int d;
		    	int b;
		    }
		    class MyComp implements Comparator<Node>{
		        
				@Override
				public int compare(Node o1, Node o2) {
					if(o1.d>o2.d){
						return 1;
					}else if(o1.d<o2.d){
						return -1;
					}else{
						return 0;
						
					}
					
					
				}
		    }