#include <bits/stdc++.h>   const double EPS = 0.0000000001;   const long long mod1 = 998244353;   const long long mod2 = 1000000007;   const long long mod3 = 1000000009;   const long long mod4 = 998244353;   const long long inf = 10000000000000000;   using namespace std;   signed main() {     cin.tie(0);     cout.tie(0);     std::ios_base::sync_with_stdio(0);     long long n, a;     cin >> n >> a;     long long matrix[a][n];     for (long long i = 0; i < a; i++) {       for (long long z = 0; z < n; z++) {         char c;         cin >> c;         matrix[i][z] = (c -  0 );       }     }     bool used[a];     for (long long i = 0; i < a; i++) {       bool p = 0;       for (long long z = 0; z < n; z++) {         if (!matrix[i][z]) p = 1;       }       used[i] = p;     }     long long c = 0;     long long x = 1;     long long maxi = -1;     for (long long i = 0; i < a; i++) {       if (used[i]) {         c++;         continue;       }       maxi = max(maxi, c);       c = 0;     }     maxi = max(maxi, c);     cout << maxi;   }   