The flag of Berland is such rectangular field n × m that satisfies following conditions:

  * Flag consists of three colors which correspond to letters 'R', 'G' and 'B'. 
  * Flag consists of three equal in width and height stripes, parralel to each other and to sides of the flag. Each stripe has exactly one color. 
  * Each color should be used in exactly one stripe. 



You are given a field n × m, consisting of characters 'R', 'G' and 'B'. Output "YES" (without quotes) if this field corresponds to correct flag of Berland. Otherwise, print "NO" (without quotes).

Input

The first line contains two integer numbers n and m (1 ≤ n, m ≤ 100) — the sizes of the field.

Each of the following n lines consisting of m characters 'R', 'G' and 'B' — the description of the field.

Output

Print "YES" (without quotes) if the given field corresponds to correct flag of Berland . Otherwise, print "NO" (without quotes).

Examples

Input

6 5
RRRRR
RRRRR
BBBBB
BBBBB
GGGGG
GGGGG


Output

YES


Input

4 3
BRG
BRG
BRG
BRG


Output

YES


Input

6 7
RRRGGGG
RRRGGGG
RRRGGGG
RRRBBBB
RRRBBBB
RRRBBBB


Output

NO


Input

4 4
RRRR
RRRR
BBBB
GGGG


Output

NO

Note

The field in the third example doesn't have three parralel stripes.

Rows of the field in the fourth example are parralel to each other and to borders. But they have different heights — 2, 1 and 1.
import java.util.*;
import java.io.*;
import java.math.BigInteger;
 
/**
 *
 * @author usquare
 */

public class ProblemH {
    
    static long mod = (int) (1e9+7);
    static InputReader in;
    static PrintWriter out;
    
    static void solve() {
        
        in = new InputReader(System.in);
        out = new PrintWriter(System.out);
        
        int n = in.nextInt();
        int m = in.nextInt();
        boolean ok = false;
        
        String[] s = new String[n];
        for(int i = 0; i < n; i++)
            s[i] = in.readString();
        
        if(n % 3 == 0){
            HashSet<Character> set = new HashSet<>();
            HashSet<Character> tmp = new HashSet<>();
            for(int i = 0; i < n/3; i++){
                for(int j = 0; j < m; j++){
                    tmp.add(s[i].charAt(j));
                }
            }
            if(tmp.size() == 1){
                set.addAll(tmp);
                tmp.clear();
                for(int i = n/3; i < 2*n/3; i++){
                    for(int j = 0; j < m; j++){
                        tmp.add(s[i].charAt(j));
                    }
                }
                if(tmp.size() == 1){
                    set.addAll(tmp);
                    tmp.clear();
                    for(int i = 2*n/3; i < n; i++){
                        for(int j = 0; j < m; j++){
                            tmp.add(s[i].charAt(j));
                        }
                    }
                    if(tmp.size() == 1){
                        set.addAll(tmp);
                        if(set.size() == 3) ok = true;
                    }
                }
            }
        }
        if(m % 3 == 0){
            HashSet<Character> set = new HashSet<>();
            HashSet<Character> tmp = new HashSet<>();
            for(int i = 0; i < m/3; i++){
                for(int j = 0; j < n; j++){
                    tmp.add(s[j].charAt(i));
                }
            }
            if(tmp.size() == 1){
                set.addAll(tmp);
                tmp.clear();
                for(int i = m/3; i < 2*m/3; i++){
                    for(int j = 0; j < n; j++){
                        tmp.add(s[j].charAt(i));
                    }
                }
                if(tmp.size() == 1){
                    set.addAll(tmp);
                    tmp.clear();
                    for(int i = 2*m/3; i < m; i++){
                        for(int j = 0; j < n; j++){
                            tmp.add(s[j].charAt(i));
                        }
                    }
                    if(tmp.size() == 1){
                        set.addAll(tmp);
                        if(set.size() == 3) ok = true;
                    }
                }
            }
        }
        
        out.println(ok ? "YES" : "NO" );
        out.close();
        
    }
    
    public static void main(String[] args) {
 
        new Thread(null,new Runnable() {
            @Override
            public void run() {
                try{
                    solve();
                }
                catch(Exception e){
                    e.printStackTrace();
                }
            }
        },"1",1<<26).start();
    }
    
    static class Pair implements Comparable<Pair>{
 
        int x,y;
        int i;
        
	Pair (int x,int y,int i){
		this.x=x;
		this.y=y;
		this.i=i;
	}
 
	Pair (int x,int y){
		this.x = x;
		this.y = y;
	}
        
	public int compareTo(Pair o) {
            return Long.compare(this.x,o.x);
		//return 0;
	}
 
        public boolean equals(Object o) {
            if (o instanceof Pair) {
                Pair p = (Pair)o;
                return p.x == x && p.y == y && p.i==i;
            }
            return false;
        }
 
        @Override
        public String toString() {
            return x+" "+y+" "+i;
        }
        
        public int hashCode() {
            return new Integer(x).hashCode() * 31 + new Integer(y).hashCode()+new Integer(i).hashCode()*37;
        }

    } 
    
    static class Merge {
        
        public static void sort(long inputArr[]) {
            int length = inputArr.length;
            doMergeSort(inputArr,0, length - 1);
        }
        
        private static void doMergeSort(long[] arr,int lowerIndex, int higherIndex) {        
            if (lowerIndex < higherIndex) {
                int middle = lowerIndex + (higherIndex - lowerIndex) / 2;
                doMergeSort(arr,lowerIndex, middle);
                doMergeSort(arr,middle + 1, higherIndex);
                mergeParts(arr,lowerIndex, middle, higherIndex);
            }
        }
        
        private static void mergeParts(long[]array,int lowerIndex, int middle, int higherIndex) {
            long[] temp=new long[higherIndex-lowerIndex+1];
            for (int i = lowerIndex; i <= higherIndex; i++) {
                temp[i-lowerIndex] = array[i];
            }
            int i = lowerIndex;
            int j = middle + 1;
            int k = lowerIndex;
            while (i <= middle && j <= higherIndex) {
                if (temp[i-lowerIndex] < temp[j-lowerIndex]) {
                    array[k] = temp[i-lowerIndex];
                    i++;
                } else {
                    array[k] = temp[j-lowerIndex];
                    j++;
                }
                k++;
            }
            while (i <= middle) {
                array[k] = temp[i-lowerIndex];
                k++;
                i++;
            }
            while(j<=higherIndex){
                array[k]=temp[j-lowerIndex];
                k++;
                j++;
            }
        }
 
    }
    
    static long add(long a,long b){
        long x=(a+b);
        while(x>=mod) x-=mod;
        return x;
    }
 
    static long sub(long a,long b){
        long x=(a-b);
        while(x<0) x+=mod;
        return x;
    }
    
    static long mul(long a,long b){
        a%=mod;
        b%=mod;
        long x=(a*b);
        return x%mod;
    }
 
    
    static boolean isPal(String s){
        for(int i=0, j=s.length()-1;i<=j;i++,j--){
                if(s.charAt(i)!=s.charAt(j)) return false;
        }
        return true;
    }
    static String rev(String s){
		StringBuilder sb=new StringBuilder(s);
		sb.reverse();
		return sb.toString();
    }
    
    static long gcd(long x,long y){
	if(y==0)
		return x;
	else
		return gcd(y,x%y);
    }
    
    static int gcd(int x,int y){
	if(y==0)
		return x;
	else 
		return gcd(y,x%y);
    }
    
    static long gcdExtended(long a,long b,long[] x){
        
        if(a==0){
            x[0]=0;
            x[1]=1;
            return b;
        }
        long[] y=new long[2];
        long gcd=gcdExtended(b%a, a, y);
        
        x[0]=y[1]-(b/a)*y[0];
        x[1]=y[0];
        
        return gcd;
    }
    
 
    static long mulmod(long  a,long b,long m) {
        if (m <= 1000000009) return a * b % m;
 
        long res = 0;
        while (a > 0) {
            if ((a&1)!=0) {
                res += b;
                if (res >= m) res -= m;
            }
            a >>= 1;
            b <<= 1;
            if (b >= m) b -= m;
        }
        return res;
    }
    
    static int abs(int a,int b){
	return (int)Math.abs(a-b);
    }
 
    public static long abs(long a,long b){
	return (long)Math.abs(a-b);
    }
    
    static int max(int a,int b){
	if(a>b)
		return a;
	else
		return b;
    }
 
    static int min(int a,int b){
	if(a>b)
		return b;
	else 
		return a;
    }
    
    static long max(long a,long b){
	if(a>b)
		return a;
	else
		return b;
    }
 
    static long min(long a,long b){
	if(a>b)
		return b;
	else 
		return a;
    }
 
    static long pow(long n,long p,long m){
	 long  result = 1;
	  if(p==0)
	    return 1;
          
	while(p!=0)
	{
	    if(p%2==1)
	        result *= n;
	    if(result>=m)
	    result%=m;
	    p >>=1;
	    n*=n;
	    if(n>=m)
	    n%=m;
	}
	return result;
    }
    
    static long pow(long n,long p){
	long  result = 1;
	  if(p==0)
	    return 1;
          
	while(p!=0)
	{
	    if(p%2==1)
	        result *= n;	    
	    p >>=1;
	    n*=n;	    
	}
	return result;
    }
    
    static void debug(Object... o) {
            System.out.println(Arrays.deepToString(o));
    }
     
    static class InputReader {
    
        private final InputStream stream;
        private final byte[] buf = new byte[8192];
        private int curChar, snumChars;
        private SpaceCharFilter filter;
 
        public InputReader(InputStream stream) {
                this.stream = stream;
        }
 
        public int snext() {
                if (snumChars == -1)
                        throw new InputMismatchException();
                if (curChar >= snumChars) {
                        curChar = 0;
                        try {
                                snumChars = stream.read(buf);
                        } catch (IOException e) {
                                throw new InputMismatchException();
                        }
                        if (snumChars <= 0)
                                return -1;
                }
                return buf[curChar++];
        }
 
        public int nextInt() {
                int c = snext();
                while (isSpaceChar(c)) {
                        c = snext();
                }
                int sgn = 1;
                if (c == '-') {
                        sgn = -1;
                        c = snext();
                }
                int res = 0;
                do {
                        if (c < '0' || c > '9')
                                throw new InputMismatchException();
                        res *= 10;
                        res += c - '0';
                        c = snext();
                } while (!isSpaceChar(c));
                return res * sgn;
        }
 
        public long nextLong() {
                int c = snext();
                while (isSpaceChar(c)) {
                        c = snext();
                }
                int sgn = 1;
                if (c == '-') {
                        sgn = -1;
                        c = snext();
                }
                long res = 0;
                do {
                        if (c < '0' || c > '9')
                                throw new InputMismatchException();
                        res *= 10;
                        res += c - '0';
                        c = snext();
                } while (!isSpaceChar(c));
                return res * sgn;
        }
 
        public int[] nextIntArray(int n) {
                int a[] = new int[n];
                for (int i = 0; i < n; i++) {
                        a[i] = nextInt();
                }
                return a;
        }
 
        public long[] nextLongArray(int n) {
                long a[] = new long[n];
                for (int i = 0; i < n; i++) {
                        a[i] = nextLong();
                }
                return a;
        }
 
        public String readString() {
                int c = snext();
                while (isSpaceChar(c)) {
                        c = snext();
                }
                StringBuilder res = new StringBuilder();
                do {
                        res.appendCodePoint(c);
                        c = snext();
                } while (!isSpaceChar(c));
                return res.toString();
        }
 
        public String nextLine() {
                int c = snext();
                while (isSpaceChar(c))
                        c = snext();
                StringBuilder res = new StringBuilder();
                do {
                        res.appendCodePoint(c);
                        c = snext();
                } while (!isEndOfLine(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;
        }
 
        private boolean isEndOfLine(int c) {
                return c == '\n' || c == '\r' || c == -1;
        }
 
        public interface SpaceCharFilter {
                public boolean isSpaceChar(int ch);
        }
        
    }
}    
 