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.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashSet;
import java.util.StringTokenizer;

public class P {

	public static void main(String args[]) throws FileNotFoundException {
		InputReader in = new InputReader(System.in);
		OutputStream outputStream = System.out;
		PrintWriter out = new PrintWriter(outputStream);
		StringBuilder sb = new StringBuilder();
		// ----------My Code----------
		int n = in.nextInt();
		int m = in.nextInt();
		char flag[][] = new char[n][m];
		HashSet<Character> al=new HashSet<Character>();
		for (int i = 0; i < n; i++)
			flag[i] = in.next().toCharArray();
		if (n % 3 == 0 || m % 3 == 0) {
			if (n % 3 == 0 && m % 3 == 0) {
				boolean ans1 = true;
				char c = flag[0][0];
				al.add(c);
				for (int i = 0; i < n / 3; i++) {
					for (int j = 0; j < m; j++) {
						if (c != flag[i][j]) {
							ans1 = false;
							break;
						}
					}
				}
				c = flag[n / 3][0];
				al.add(c);
				for (int i = n / 3; i < 2 * n / 3; i++) {
					for (int j = 0; j < m; j++) {
						if (c != flag[i][j]) {
							ans1 = false;
							break;
						}
					}
				}
				c = flag[2 * n / 3][0];
				al.add(c);
				for (int i = 2 * n / 3; i < n; i++) {
					for (int j = 0; j < m; j++) {
						if (c != flag[i][j]) {
							ans1 = false;
							break;
						}
					}
				}
				if(al.size()!=3)
					ans1=false;
				al=new HashSet<>();
				boolean ans = true;
				c = flag[0][0];
				al.add(c);
				for (int i = 0; i < m / 3; i++) {
					for (int j = 0; j < n; j++) {
						if (c != flag[j][i]) {
							ans = false;
							break;
						}
					}
				}
				c = flag[0][m / 3];
				al.add(c);
				for (int i = m / 3; i < 2 * m / 3; i++) {
					for (int j = 0; j < n; j++) {
						if (c != flag[j][i]) {
							ans = false;
							break;
						}
					}
				}
				c = flag[0][2 * m / 3];
				al.add(c);
				for (int i = 2 * m / 3; i < m; i++) {
					for (int j = 0; j < n; j++) {
						if (c != flag[j][i]) {
							ans = false;
							break;
						}
					}
				}
				if(al.size()!=3)
					ans=false;
				System.out.println((ans == true || ans1 == true) ? "YES" : "NO");
			} else if (n % 3 == 0) {
				boolean ans = true;
				char c = flag[0][0];
				al.add(c);
				for (int i = 0; i < n / 3; i++) {
					for (int j = 0; j < m; j++) {
						if (c != flag[i][j]) {
							ans = false;
							break;
						}
					}
				}
				c = flag[n / 3][0];
				al.add(c);
				for (int i = n / 3; i < 2 * n / 3; i++) {
					for (int j = 0; j < m; j++) {
						if (c != flag[i][j]) {
							ans = false;
							break;
						}
					}
				}
				c = flag[2 * n / 3][0];
				al.add(c);
				for (int i = 2 * n / 3; i < n; i++) {
					for (int j = 0; j < m; j++) {
						if (c != flag[i][j]) {
							ans = false;
							break;
						}
					}
				}
				if(al.size()!=3)
					ans=false;
				System.out.println(ans == true ? "YES" : "NO");
			} else {
				boolean ans = true;
				char c = flag[0][0];
				al.add(c);
				for (int i = 0; i < m / 3; i++) {
					for (int j = 0; j < n; j++) {
						if (c != flag[j][i]) {
							ans = false;
							break;
						}
					}
				}
				c = flag[0][m / 3];
				al.add(c);
				for (int i = m / 3; i < 2 * m / 3; i++) {
					for (int j = 0; j < n; j++) {
						if (c != flag[j][i]) {
							ans = false;
							break;
						}
					}
				}
				c = flag[0][2 * m / 3];
				al.add(c);
				for (int i = 2 * m / 3; i < m; i++) {
					for (int j = 0; j < n; j++) {
						if (c != flag[j][i]) {
							ans = false;
							break;
						}
					}
				}
				if(al.size()!=3)
					ans=false;
				System.out.println(ans == true ? "YES" : "NO");
			}
		} else {
			System.out.println("NO");
		}
		// ---------------The End------------------

		out.close();
	}

	static boolean isPossible(int x, int y) {
		if (x >= 0 && y >= 0 && x < 4 && y < 4)
			return true;
		return false;
	}
	// ---------------Extra Methods------------------

	public static long pow(long x, long n, long mod) {
		long res = 1;
		x %= mod;
		while (n > 0) {
			if (n % 2 == 1) {
				res = (res * x) % mod;
			}
			x = (x * x) % mod;
			n /= 2;
		}
		return res;
	}

	public 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;
	}

	public static String rev(String s) {
		StringBuilder sb = new StringBuilder(s);
		sb.reverse();
		return sb.toString();
	}

	public static long gcd(long x, long y) {
		if (x % y == 0)
			return y;
		else
			return gcd(y, x % y);
	}

	public static int gcd(int x, int y) {
		if (x % y == 0)
			return y;
		else
			return gcd(y, x % y);
	}

	public 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;
	}

	public 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);
	}

	public static int max(int a, int b) {
		if (a > b)
			return a;
		else
			return b;
	}

	public static int min(int a, int b) {
		if (a > b)
			return b;
		else
			return a;
	}

	public static long max(long a, long b) {
		if (a > b)
			return a;
		else
			return b;
	}

	public static long min(long a, long b) {
		if (a > b)
			return b;
		else
			return a;
	}
	// ---------------Extra Methods------------------

	public static void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}

	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream inputstream) {
			reader = new BufferedReader(new InputStreamReader(inputstream));
			tokenizer = null;
		}

		public String nextLine() {
			String fullLine = null;
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					fullLine = reader.readLine();
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
				return fullLine;
			}
			return fullLine;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public char nextChar() {
			return next().charAt(0);
		}

		public long nextLong() {
			return Long.parseLong(next());
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}

		public int[] nextIntArray(int n, int f) {
			if (f == 0) {
				int[] arr = new int[n];
				for (int i = 0; i < n; i++) {
					arr[i] = nextInt();
				}
				return arr;
			} else {
				int[] arr = new int[n + 1];
				for (int i = 1; i < n + 1; i++) {
					arr[i] = nextInt();
				}
				return arr;
			}
		}

		public long[] nextLongArray(int n, int f) {
			if (f == 0) {
				long[] arr = new long[n];
				for (int i = 0; i < n; i++) {
					arr[i] = nextLong();
				}
				return arr;
			} else {
				long[] arr = new long[n + 1];
				for (int i = 1; i < n + 1; i++) {
					arr[i] = nextLong();
				}
				return arr;
			}

		}

		public double[] nextDoubleArray(int n, int f) {
			if (f == 0) {
				double[] arr = new double[n];
				for (int i = 0; i < n; i++) {
					arr[i] = nextDouble();
				}
				return arr;
			} else {
				double[] arr = new double[n + 1];
				for (int i = 1; i < n + 1; i++) {
					arr[i] = nextDouble();
				}
				return arr;
			}
		}

	}

	static class Pair implements Comparable<Pair> {
		int a, b;

		Pair(int a, int b) {
			this.a = a;
			this.b = b;
		}

		public int compareTo(Pair o) {
			// TODO Auto-generated method stub
			if (this.a != o.a)
				return Integer.compare(this.a, o.a);
			else
				return Integer.compare(this.b, o.b);
		}

		public boolean equals(Object o) {
			if (o instanceof Pair) {
				Pair p = (Pair) o;
				return p.a == a && p.b == b;
			}
			return false;
		}

		public int hashCode() {
			return new Integer(a).hashCode() * 31 + new Integer(b).hashCode();
		}

	}

}