#include <bits/stdc++.h>
using namespace std;
const int N = 2e2 + 10, oo = 1e9 + 10, MOD = 1e9 + 7;
int n, m;
char a[N][N];
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) cin >> a[i][j];
  }
  if (n % 3 && m % 3) {
    cout << "NO\n";
    return 0;
  }
  if (n % 3 == 0) {
    int q = 0, r = 0, b = 0, g = 0;
    for (int i = 1; i <= n; i++) {
      for (int j = 2; j <= m; j++) {
        if (a[i][j] != a[i][j - 1]) q = 1;
      }
      if (i <= n / 3) {
        if (i > 1 && a[i][1] != a[i - 1][1]) q = 1;
        continue;
      }
      if (i > n / 3 && i <= 2 * n / 3) {
        if (i > n / 3 + 1 && a[i][1] != a[i - 1][1]) q = 1;
        continue;
      }
      if (i > 2 * n / 3 + 1 && a[i][1] != a[i - 1][1]) q = 1;
    }
    if (a[1][1] == 'R') r++;
    if (a[n / 3 + 1][1] == 'R') r++;
    if (a[2 * n / 3 + 1][1] == 'R') r++;
    if (a[1][1] == 'G') g++;
    if (a[n / 3 + 1][1] == 'G') g++;
    if (a[2 * n / 3 + 1][1] == 'G') g++;
    if (a[1][1] == 'B') b++;
    if (a[n / 3 + 1][1] == 'B') b++;
    if (a[2 * n / 3 + 1][1] == 'B') b++;
    if (r == b && b == g && !q) {
      cout << "YES\n";
      return 0;
    }
  }
  if (m % 3 == 0) {
    int q = 0, r = 0, b = 0, g = 0;
    for (int j = 1; j <= m; j++) {
      for (int i = 2; i <= n; i++) {
        if (a[i][j] != a[i - 1][j]) q = 1;
      }
      if (j <= m / 3) {
        if (j > 1 && a[1][j] != a[1][j - 1]) q = 1;
        continue;
      }
      if (j > m / 3 && j <= 2 * m / 3) {
        if (j > m / 3 + 1 && a[1][j] != a[1][j - 1]) q = 1;
        continue;
      }
      if (j > 2 * m / 3 + 1 && a[1][j] != a[1][j - 1]) q = 1;
    }
    if (a[1][1] == 'R') r++;
    if (a[1][m / 3 + 1] == 'R') r++;
    if (a[1][2 * m / 3 + 1] == 'R') r++;
    if (a[1][1] == 'G') g++;
    if (a[1][m / 3 + 1] == 'G') g++;
    if (a[1][2 * m / 3 + 1] == 'G') g++;
    if (a[1][1] == 'B') b++;
    if (a[1][m / 3 + 1] == 'B') b++;
    if (a[1][2 * m / 3 + 1] == 'B') b++;
    if (r == b && b == g && !q) {
      cout << "YES\n";
      return 0;
    }
  }
  cout << "NO\n";
}
