#include <bits/stdc++.h>
using namespace std;
vector<vector<char> > a;
vector<long> ok;
int main() {
  long n, m;
  cin >> n >> m;
  cin.ignore(1);
  a.assign(n, vector<char>(m, '0'));
  for (long i = 0; i < n; i++)
    for (long j = 0; j < m; j++) cin >> a[i][j];
  ok.assign(m, 0);
  for (long i = 0; i < n; i++)
    for (long j = 0; j < m; j++) {
      if (a[i][j] == '1') ok[j]++;
    }
  long dem = 0;
  bool f = false;
  for (long i = 0; i < n; i++) {
    dem = 0;
    for (long j = 0; j < m; j++) {
      if (a[i][j] == '1') {
        if (ok[j] > 1) dem++;
      } else {
        dem++;
      }
    }
    if (dem == m) f = true;
  }
  if (f)
    cout << "YES";
  else
    cout << "NO";
}
