func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     vector<long long> v;     long long t, p;     char c;     int n, k;     cin >> n >> k;     for (int i = 0; i < n; i++) {       p = 0ll;       cin >> t >> c;       p = ((p << 8) | t);       cin >> t >> c;       p = ((p << 8) | t);       cin >> t >> c;       p = ((p << 8) | t);       cin >> t;       p = ((p << 8) | t);       v.push_back(p);     }     long long sub = 0ll;     for (long long i = 31; i >= 0; i--) {       sub = (sub | (1ll << i));       set<long long> s;       for (int j = 0; j < n; j++) {         s.insert(v[j] & sub);       }       if (s.size() == k)         break;       else if (s.size() > k) {         sub = -1;         break;       }     }     if (sub == -1)       cout <<  -1  << endl;     else {       vector<long long> last;       last.push_back(sub & ((1ll << 8) - 1ll));       sub = (sub >> 8);       last.push_back(sub & ((1ll << 8) - 1ll));       sub = (sub >> 8);       last.push_back(sub & ((1ll << 8) - 1ll));       sub = (sub >> 8);       last.push_back(sub & ((1ll << 8) - 1ll));       cout << last[3] <<  .  << last[2] <<  .  << last[1] <<  .  << last[0]            << endl;     }     return 0;   }   