func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int N, M, k;     string in;     list<string> ret;     cin >> N >> M;     cin >> in >> k;     if (k == 0) {       for (int i = 0; i < N; i++) in[i] = ((in[i] -  0 ) ^ 1) +  0 ;       ret.push_back(in);     } else {       long long s = (1LL << k) - 1;       while (!(s & 1LL << N)) {         string c = in;         for (int i = 0; i < N; i++)           if (!(s & (1LL << i))) c[i] = ((c[i] -  0 ) ^ 1) +  0 ;         ret.push_back(c);         long long lo = s & ~(s - 1);         long long lz = (s + lo) & ~s;         s |= lz;         s &= ~(lz - 1);         s |= (lz / lo / 2) - 1;       }     }     for (int i = 1; i < M; i++) {       cin >> in >> k;       list<string>::iterator it = ret.begin();       while (it != ret.end()) {         int c = 0;         for (int j = 0; j < N; j++)           if ((*it)[j] == in[j]) c++;         if (c != k)           it = ret.erase(it);         else           it++;       }     }     cout << ret.size();     return 0;   }   