Anadi has a set of dominoes. Every domino has two parts, and each part contains some dots. For every a and b such that 1 ≤ a ≤ b ≤ 6, there is exactly one domino with a dots on one half and b dots on the other half. The set contains exactly 21 dominoes. Here is an exact illustration of his set:

<image>

Also, Anadi has an undirected graph without self-loops and multiple edges. He wants to choose some dominoes and place them on the edges of this graph. He can use at most one domino of each type. Each edge can fit at most one domino. It's not necessary to place a domino on each edge of the graph.

When placing a domino on an edge, he also chooses its direction. In other words, one half of any placed domino must be directed toward one of the endpoints of the edge and the other half must be directed toward the other endpoint. There's a catch: if there are multiple halves of dominoes directed toward the same vertex, each of these halves must contain the same number of dots.

How many dominoes at most can Anadi place on the edges of his graph?

Input

The first line contains two integers n and m (1 ≤ n ≤ 7, 0 ≤ m ≤ (n⋅(n-1))/(2)) — the number of vertices and the number of edges in the graph.

The next m lines contain two integers each. Integers in the i-th line are a_i and b_i (1 ≤ a, b ≤ n, a ≠ b) and denote that there is an edge which connects vertices a_i and b_i.

The graph might be disconnected. It's however guaranteed that the graph doesn't contain any self-loops, and that there is at most one edge between any pair of vertices.

Output

Output one integer which denotes the maximum number of dominoes which Anadi can place on the edges of the graph.

Examples

Input


4 4
1 2
2 3
3 4
4 1


Output


4


Input


7 0


Output


0


Input


3 1
1 3


Output


1


Input


7 21
1 2
1 3
1 4
1 5
1 6
1 7
2 3
2 4
2 5
2 6
2 7
3 4
3 5
3 6
3 7
4 5
4 6
4 7
5 6
5 7
6 7


Output


16

Note

Here is an illustration of Anadi's graph from the first sample test:

<image>

And here is one of the ways to place a domino on each of its edges:

<image>

Note that each vertex is faced by the halves of dominoes with the same number of dots. For instance, all halves directed toward vertex 1 have three dots.
    import java.io.BufferedWriter;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.io.OutputStreamWriter;
    import java.io.PrintWriter;
    import java.io.Writer;
    import java.util.Arrays;
    import java.util.InputMismatchException;
    import java.util.*;
    import java.io.*;
    import java.math.*;
    public class Main7{
     
    static class Pair
        { 
            int x;
            int y;
            public Pair(int x,int y) 
            {     
                this.x= x; 
                this.y= y;
            }     
            
        @Override
                public int hashCode() 
                { 
                    final int temp = 14; 
                    int ans = 1; 
                    ans =x*31+y*13; 
                    return ans; 
                } 
          
                // Equal objects must produce the same 
                // hash code as long as they are equal 
            @Override
            public boolean equals(Object o) 
            { 
                if (this == o) { 
                    return true; 
                } 
                if (o == null) { 
                    return false; 
                } 
                if (this.getClass() != o.getClass()) { 
                    return false; 
                } 
                Pair other = (Pair)o; 
                if (this.x != other.x || this.y!=other.y) { 
                    return false; 
                } 
                return true; 
            } 
                
        } 
        static class Pair1
        {
            String x;
            int y;
            int z;
            
        }
        static class Compare
        { 
            static void compare(Pair arr[], int n) 
            { 
                // Comparator to sort the pair according to second element 
            /*    Arrays.sort(arr, new Comparator<Pair>() { 
                    @Override public int compare(Pair p1, Pair p2) 
                    { 
                        if(p1.start>p2.start)
                        {
                            return 1;
                        }
                        else if(p1.start==p2.start)
                        {
                            return 0;
                        }
                        else
                        {
                            return -1;
                        }
                    } 
                }); */
            }
            
        }
        
        
        public static long pow(long a, long b)
        {
            long result=1;
            while(b>0)
            {
                if (b % 2 != 0)
                {
                    result=(result*a)%998244353;
                    b--;
                } 
                a=(a*a)%998244353;
                b /= 2;
            }   
            return result;
        }
        public static long fact(long num)
        {
                    long value=1;
                    int i=0;
                    for(i=2;i<num;i++)
                    {
                        value=((value%mod)*i%mod)%mod;
                    }
                    return value;
                }
                public static long gcd(long a, long b)
                {
                    if (a == 0)
                        return b;
                    return gcd(b%a, a);
                }
                
        /*        public static long lcm(long a,long b)
                {
                    return a * (b / gcd(a, b));
                }
            */    public static long sum(int h)
                {
                    return (h*(h+1)/2);
                }
                public static void dfs(int parent,boolean[] visited,int[] dp)
                {
                    ArrayList<Integer> arr=new ArrayList<Integer>();
                    arr=graph.get(parent);
                    visited[parent]=true;
                    for(int i=0;i<arr.size();i++)
                    {
                        int num=(int)arr.get(i);
                        if(visited[num]==false)
                        {
                            dfs(num,visited,dp);
                        }
                        dp[parent]=Math.max(dp[num]+1,dp[parent]);
                    }
                }
            //    static int flag1=0;
                static int[] dis;
                static int mod=1000000007;
                static ArrayList<ArrayList<Integer>> graph;
                
                public static void bfs(int num,int size)
                {
                    boolean[] visited=new boolean[size+1];
                    Queue<Integer> q=new LinkedList<>();
                    q.add(num);
                    ans[num]=1;
                    visited[num]=true;
                    while(!q.isEmpty())
                    {
                        int x=q.poll();
                        ArrayList<Integer> al=graph.get(x);
                        for(int i=0;i<al.size();i++)
                        {
                            int y=al.get(i);    
                            if(visited[y]==false)
                            {
                                q.add(y);
                                ans[y]=ans[x]+1;
                                visited[y]=true;
                            }
                        }
                    }
                }
                static int[] ans;
                
                
                
                
                
                
                
                
                
            //    static int[] a;              
                public static int[] sort(int[] a)
                {
                    int n=a.length;
                    ArrayList<Integer> ar=new ArrayList<>();
                    for(int i=0;i<a.length;i++)
                    {
                        ar.add(a[i]);
                    }
                    Collections.sort(ar);
                    for(int i=0;i<n;i++)
                    {
                        a[i]=ar.get(i);
                    }
                    return a;
                }
                static public void main(String args[])throws IOException
                {
                    int n1=i();
					int m1=i();
					int[] a=new int[m1];
					int[] b=new int[m1];
					for(int i=0;i<m1;i++)
					{
						a[i]=i()-1;
						b[i]=i()-1;
					}
					int c=0;
					int max=0;
					for(int i=6;i>=0;i--)
					{
						for(int j=6;j>=0;j--)
						{
							for(int k=6;k>=0;k--)
							{
								for(int l=6;l>=0;l--)
								{
									for(int m=6;m>=0;m--)
									{
										for(int n=6;n>=0;n--)
										{
											for(int o=6;o>=0;o--)
											{
												int ans=0;
												int[] x=new int[]{i,j,k,l,m,n,o};
												HashMap<ArrayList<Integer>,Integer> hash=new HashMap<>();
												for(int p=0;p<m1;p++)
												{
													int num=a[p];
													int num1=b[p];
													if(x[a[p]]==0 || x[b[p]]==0)
													{
														continue;
													}
													else
													{
														ArrayList<Integer> ar=new ArrayList<>();
														ar.add(x[a[p]]);
														ar.add(x[b[p]]);
														ArrayList<Integer> ar1=new ArrayList<>();
														ar1.add(x[b[p]]);
														ar1.add(x[a[p]]);
														if(hash.containsKey(ar)==false && hash.containsKey(ar1)==false)
														{
															ans++;
															hash.put(ar,1);
															ar.clear();
															ar.add(x[b[p]]);
															ar.add(x[a[p]]);
															hash.put(ar,1);
															if(ans==m1)
															{
																pln(m1+"");
																return;
															}
															if(c++==200000)
															{
																pln(max+"");
																return ;
															}
															
														}
													}
												}
												max=Math.max(ans,max);
											}
										}
									}
								
								}
							}
						}
					}
					pln(max+"");
                }
                
                /**/
                static InputReader in=new InputReader(System.in);
                    static OutputWriter out=new OutputWriter(System.out);
                    public static long l()
                    {
                        String s=in.String();
                        return Long.parseLong(s);
                    }
                    public static void pln(String value)
                    {
                        System.out.println(value);
                    }
                    public static int i()
                    {
                        return in.Int();
                    }
                    public static String s()
                    {
                        return in.String();
                    }
        }
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
             
            class InputReader {
                 
                private InputStream stream;
                private byte[] buf = new byte[1024];
                private int curChar;
                private int numChars;
                private SpaceCharFilter filter;
             
                public InputReader(InputStream stream) {
                    this.stream = stream;
                }
             
                public 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++];
                }
             
                public int Int() {
                    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;
                }
             
                public String String() {
                    int c = read();
                    while (isSpaceChar(c))
                        c = read();
                    StringBuilder res = new StringBuilder();
                    do {
                        res.appendCodePoint(c);
                        c = read();
                    } while (!isSpaceChar(c));
                    return res.toString();
                }
             
                public boolean isSpaceChar(int c) {
                    if (filter != null)
                        return filter.isSpaceChar(c);
                    return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
                }
             
                public String next() {
                    return String();
                }
             
                public interface SpaceCharFilter {
                    public boolean isSpaceChar(int ch);
                }
            }
             
            class OutputWriter {
                private final PrintWriter writer;
             
                public OutputWriter(OutputStream outputStream) {
                    writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
                }
             
                public OutputWriter(Writer writer) {
                    this.writer = new PrintWriter(writer);
                }
             
                public void print(Object...objects) {
                    for (int i = 0; i < objects.length; i++) {
                        if (i != 0)
                            writer.print(' ');
                        writer.print(objects[i]);
                    }
                }
             
                public void printLine(Object...objects) {
                    print(objects);
                    writer.println();
                }
             
                public void close() {
                    writer.close();
                }
             
                public void flush() {
                    writer.flush();
                }
             
                }
             
                class IOUtils {
             
                public static int[] readIntArray(InputReader in, int size) {
                    int[] array = new int[size];
                    for (int i = 0; i < size; i++)
                        array[i] = in.Int();
                    return array;
                }
             
                } 
     