func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<long long> addr;   void psh(string s) {     long long res = 0, cur = 0;     for (int i = 0; i < s.size(); i++) {       if (s[i] ==  . ) {         res *= 256;         res += cur;         cur = 0;       } else {         cur *= 10;         cur += (s[i] -  0 );       }     }     res *= 256;     res += cur;     addr.push_back(res);   }   void outp(long long mask) {     int d = mask % 256;     mask /= 256;     int c = mask % 256;     mask /= 256;     int b = mask % 256;     mask /= 256;     int a = mask;     printf( %d.%d.%d.%d n , a, b, c, d);   }   set<long long> s;   int main() {     int n, k;     cin >> n >> k;     for (int i = 0; i < n; i++) {       string s;       cin >> s;       psh(s);     }     long long mask = 0;     for (int i = 31; i >= 0; i--) {       mask += (1ll << i);       s.clear();       for (int i = 0; i < n; i++) {         s.insert(addr[i] & mask);       }       if (s.size() == k) {         outp(mask);         return 0;       }     }     cout << -1 << endl;     return 0;   }   