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.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws FileNotFoundException {
        ConsoleIO io = new ConsoleIO(new InputStreamReader(System.in), new PrintWriter(System.out));
        //String test = "C-small-attempt0";
        //ConsoleIO io = new ConsoleIO(new FileReader("D:\\Dropbox\\code\\practice\\jb\\src\\" + test + ".in"), new PrintWriter(new File("D:\\Dropbox\\code\\practice\\jb\\src\\" + test + "-out.txt")));

       new Main(io).solve();

        io.close();
    }

    ConsoleIO io;
    Main(ConsoleIO io) {
        this.io = io;
    }

    List<List<Integer>> gr = new ArrayList<>();
    long MOD = 1_000_000_007;

    public void solve() {
        int[] l = io.readIntArray();
        int n = l[0], m = l[1];
        char[][] flag = new char[n][];
        for (int i = 0; i < n; i++) {
            flag[i] = io.readLine().trim().toCharArray();
        }

        if (n % 3 == 0) {
            int t = n / 3;
            boolean good = true;
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++) {
                    int cur = flag[i][j];
                    int b = (i / t) * t;
                    if (cur != flag[b][0])
                        good = false;
                    for (int q = 0; q < n; q+=t)
                        if (q != b && flag[q][0] == cur)
                            good = false;
                }
            if (good) {
                io.writeLine("YES");
                return;
            }
        }
        if (m % 3 == 0) {
            int t = m / 3;
            boolean good = true;
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++) {
                    int cur = flag[i][j];
                    int b = (j / t) * t;
                    if (cur != flag[0][b])
                        good = false;
                    for (int q = 0; q < m; q+=t)
                        if (q != b && flag[0][q] == cur)
                            good = false;
                }
            if (good) {
                io.writeLine("YES");
                return;
            }
        }

        io.writeLine("NO");
    }



}

class ConsoleIO {
    BufferedReader br;
    PrintWriter out;
    public ConsoleIO(Reader reader, PrintWriter writer){br = new BufferedReader(reader);out = writer;}
    public void flush(){this.out.flush();}
    public void close(){this.out.close();}
    public void writeLine(String s) {this.out.println(s);}
    public void writeInt(int a) {this.out.print(a);this.out.print(' ');}
    public void writeWord(String s){
        this.out.print(s);
    }
    public void writeIntArray(int[] a, int k, String separator) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < k; i++) {
            if (i > 0) sb.append(separator);
            sb.append(a[i]);
        }
        this.writeLine(sb.toString());
    }
    public int read(char[] buf, int len){try {return br.read(buf,0,len);}catch (Exception ex){ return -1; }}
    public String readLine() {try {return br.readLine();}catch (Exception ex){ return "";}}
    public long[] readLongArray() {
        String[]n=this.readLine().trim().split("\\s+");long[]r=new long[n.length];
        for(int i=0;i<n.length;i++)r[i]=Long.parseLong(n[i]);
        return r;
    }
    public int[] readIntArray() {
        String[]n=this.readLine().trim().split("\\s+");int[]r=new int[n.length];
        for(int i=0;i<n.length;i++)r[i]=Integer.parseInt(n[i]);
        return r;
    }
    public int[] readIntArray(int n) {
        int[] res = new int[n];
        char[] all = this.readLine().toCharArray();
        int cur = 0;boolean have = false;
        int k = 0;
        boolean neg = false;
        for(int i = 0;i<all.length;i++){
            if(all[i]>='0' && all[i]<='9'){
                cur = cur*10+all[i]-'0';
                have = true;
            }else if(all[i]=='-') {
                neg = true;
            }
            else if(have){
                res[k++] = neg?-cur:cur;
                cur = 0;
                have = false;
                neg = false;
            }
        }
        if(have)res[k++] = neg?-cur:cur;
        return res;
    }
    public int ri() {
        try {
            int r = 0;
            boolean start = false;
            boolean neg = false;
            while (true) {
                int c = br.read();
                if (c >= '0' && c <= '9') {
                    r = r * 10 + c - '0';
                    start = true;
                } else if (!start && c == '-') {
                    start = true;
                    neg = true;
                } else if (start || c == -1) return neg ? -r : r;
            }
        } catch (Exception ex) {
            return -1;
        }
    }
    public long readLong() {
        try {
            long r = 0;
            boolean start = false;
            boolean neg = false;
            while (true) {
                int c = br.read();
                if (c >= '0' && c <= '9') {
                    r = r * 10 + c - '0';
                    start = true;
                } else if (!start && c == '-') {
                    start = true;
                    neg = true;
                } else if (start || c == -1) return neg ? -r : r;
            }
        } catch (Exception ex) {
            return -1;
        }
    }
    public String readWord() {
        try {
            boolean start = false;
            StringBuilder sb = new StringBuilder();
            while (true) {
                int c = br.read();
                if (c!= ' ' && c!= '\r' && c!='\n' && c!='\t') {
                    sb.append((char)c);
                    start = true;
                } else if (start || c == -1) return sb.toString();
            }
        } catch (Exception ex) {
            return "";
        }
    }
    public char readSymbol() {
        try {
            while (true) {
                int c = br.read();
                if (c != ' ' && c != '\r' && c != '\n' && c != '\t') {
                    return (char) c;
                }
            }
        } catch (Exception ex) {
            return 0;
        }
    }
    //public char readChar(){try {return (char)br.read();}catch (Exception ex){ return 0; }}
}
class Pair {
    public Pair(int a, int b) {this.a = a;this.b = b;}
    public int a;
    public int b;
}
class PairLL {
    public PairLL(long a, long b) {this.a = a;this.b = b;}
    public long a;
    public long b;
}
class Triple {
    public Triple(int a, int b, int c) {this.a = a;this.b = b;this.c = c;}
    public int a;
    public int b;
    public int c;
}