#include <bits/stdc++.h>   using namespace std;   int op, d;   int main() {     int nc = 0, bst = 0;     ;     for (cin >> op >> d; d--;) {       string s;       cin >> s;       int c = 0;       for (int i = 0; i < s.size(); ++i)         if (s[i] ==  1 ) ++c;       if (c == op)         nc = 0;       else         ++nc;       bst = max(nc, bst);     }     cout << bst;   }   