func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, i = 0;     string a, b;     vector<pair<string, string> > vec;     cin >> n;     while (n--) {       cin >> a >> b;       vec.push_back(make_pair(a, b));     }     n = 0;     sort(vec.begin(), vec.end());     while (i < vec.size()) {       n++;       while (i < vec.size() - 1 && vec[i].first == vec[i + 1].first &&              vec[i].second == vec[i + 1].second)         i++;       i++;     }     cout << n << endl;   }   