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.lang.reflect.Array;
        import java.util.Scanner;
        import java.io.*;
        import java.util.*;
        import java.math.*;
        import java.lang.*;
        import static java.lang.Math.*;
        public class main implements Runnable {

            static ArrayList<Integer> adj[];

            static void Check2(int n) {
                adj = new ArrayList[n + 1];
                for (int i = 0; i <= n; i++) {
                    adj[i] = new ArrayList<>();
                }

            }

            static void add(int i, int j) {
        adj[i].add(j);
        adj[j].add(i);
            }

            public static void main(String[] args) {
                new Thread(null, new main(), "Check2", 1 << 26).start();// to increse stack size in java
            }

            static long mod = (long) (1e9 + 7);

            public void run() {
                            /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
                //Scanner in=new Scanner(System.in);

                InputReader in = new InputReader(System.in);
                PrintWriter w = new PrintWriter(System.out);


                    int n=in.nextInt();
                    int m=in.nextInt();
                    String s[]=new String[n];
                    char c[][]=new char[n][m];
                    for(int i=0;i<n;i++){
                        s[i]=in.next();
                        c[i]=s[i].toCharArray();
                    }

                    int flag=0;
                    for(int i=1;i<m;i++){
                        if(c[0][i]!=c[0][i-1])flag=1;
                    }
                    if(flag==0){

                    int a[]=new int[6];
                    int flag2=0;
                    for (int i=0;i<n;i++){

                        for (int j=1;j<m;j++){

                            if(c[i][j]!=c[i][j-1])flag2=1;
                        }

                        if(i>0){
                            if(c[i-1][0]!=c[i][0]&&(width(c[i][0],a)>=1))flag2=1;
                        }

                        for (int j=0;j<m;j++){
                            get(c[i][0],a,2);
                        }
                        get(c[i][0],a,1);

                    }
                    for(int i=2;i<6;i++){
                        if(a[i]!=a[i-2])flag2=1;
                    }
                    if(flag2==0)w.println("yes");
                        else w.println("no");


                    }
                    else{

                        int a[]=new int[6];
                        int flag2=0;
                        for (int i=0;i<m;i++){

                            for (int j=1;j<n;j++){

                                if(c[j][i]!=c[j-1][i])flag2=1;
                            }

                            if(i>0){
                                if(c[0][i]!=c[0][i-1]&&(hei(c[0][i],a)>=1))flag2=1;
                            }

                            for (int j=0;j<n;j++){
                                get(c[0][i],a,1);
                            }
                            get(c[0][i],a,2);

                        }
                   //     w.println(flag2);
                        for(int i=2;i<6;i++){
                            if(a[i]!=a[i-2])flag2=1;
                        }
                        if(flag2==0)w.println("yes");
                        else w.println("no");



                    }












                  w.close();
            }


            static int hei(char c,int a[]){
                if(c=='R'){
                    return a[0];
                }
                else  if(c=='B'){
                    return  a[2];
                }
                else
                    return a[4];

            }
            static int width(char c,int a[]){
                if(c=='R'){
                    return a[1];
                }
                else  if(c=='B'){
                    return  a[3];
                }
                else
                    return a[5];

            }
static void get(char c,int a[],int type){

                if(c=='R'){

                    if(type==1){
                     a[0]++;
                    }
                    else{
                        a[1]++;
                    }
                }
                if(c=='B'){


                    if(type==1){
    a[2]++;
                        }
                    else{
a[3]++;
                    }
                }
                if(c=='G'){


                    if(type==1){
a[4]++;
                    }
                    else{
a[5]++;
                    }
                }






}


                static class pair{

            int a,b,c;
                pair(int d,int e) {
                    a = d;
                    b = e;
                }


            }





            static long power(long x,long y){
                if(y==0)return 1%mod;
                if(y==1)return x%mod;


                long res=1;
                x=x%mod;
                while(y>0){


                    if((y%2)!=0){
                        res=(res*x)%mod;
                    }


                    y=y/2;
                    x=(x*x)%mod;
                }


                return res;



            }


            static  int gcd(int a,int b){

                if(b==0)return a;
                return gcd(b,a%b);
            }

            static  void sev(int a[],int n){

                for(int i=2;i<=n;i++)a[i]=i;
                for(int i=2;i<=n;i++){

                    if(a[i]!=0){
                        for(int j=2*i;j<=n;){

                            a[j]=0;
                            j=j+i;
                        }
                    }

                }

            }


            static class node{

                int y;
                int val;

                node(int a,int b){

                    y=a;
                    val=b;

                }


            }

            static 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 String nextLine()
                {
                    BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
                    String str = "";
                    try
                    {
                        str = br.readLine();
                    }
                    catch (IOException e)
                    {
                        e.printStackTrace();
                    }
                    return str;
                }
                public 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;
                }

                public 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;
                }

                public double nextDouble()
                {
                    int c = read();
                    while (isSpaceChar(c))
                        c = read();
                    int sgn = 1;
                    if (c == '-')
                    {
                        sgn = -1;
                        c = read();
                    }
                    double res = 0;
                    while (!isSpaceChar(c) && c != '.')
                    {
                        if (c == 'e' || c == 'E')
                            return res * Math.pow(10, nextInt());
                        if (c < '0' || c > '9')
                            throw new InputMismatchException();
                        res *= 10;
                        res += c - '0';
                        c = read();
                    }
                    if (c == '.')
                    {
                        c = read();
                        double m = 1;
                        while (!isSpaceChar(c))
                        {
                            if (c == 'e' || c == 'E')
                                return res * Math.pow(10, nextInt());
                            if (c < '0' || c > '9')
                                throw new InputMismatchException();
                            m /= 10;
                            res += (c - '0') * m;
                            c = read();
                        }
                    }
                    return res * sgn;
                }

                public String readString()
                {
                    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 readString();
                }

                public interface SpaceCharFilter
                {
                    public boolean isSpaceChar(int ch);
                }
            }







        }