func_code_string: #include <bits/stdc++.h>   using namespace std;   map<long long, long long> mp;   int main() {     long long k, i;     cin >> k;     string s;     cin >> s;     long long ans = 0, cnt = 0;     long long n = s.length();     mp[0] = 1;     for (i = 0; i < n; i++) {       if (s[i] ==  1 ) {         cnt++;       }       if (cnt >= k) {         ans += mp[cnt - k];       }       mp[cnt]++;     }     cout << ans;   }   