#include <bits/stdc++.h>
using namespace std;
int n, m;
char a[2100][2100];
int sum[2100];
int b[2100];
int main() {
  memset(b, 0, sizeof(b));
  memset(sum, 0, sizeof(sum));
  cin >> m >> n;
  for (int i = 1; i <= m; ++i) {
    for (int j = 1; j <= n; ++j) {
      cin >> a[i][j];
      b[j] += (a[i][j] - '0');
    }
  }
  bool ok;
  for (int i = 1; i <= m; ++i) {
    ok = 1;
    for (int j = 1; j <= n; ++j) {
      sum[j] = b[j] - a[i][j] + '0';
    }
    for (int j = 1; j <= n; ++j) {
      if (sum[j] == 0) {
        ok = 0;
        break;
      }
    }
    if (ok) {
      break;
    }
  }
  if (ok)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
