func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<pair<int, pair<char, string>>> vec;   int main() {     unsigned long long int n, i, j, n1, cnt = 0;     cin >> n;     string s;     char r;     for (i = 1; i <= n; i++) {       cin >> s;       n1 = s.size();       cnt = 0;       for (j = 0; j < n1; j++) {         if (s[j] ==  a  || s[j] ==  e  || s[j] ==  i  || s[j] ==  o  ||             s[j] ==  u ) {           cnt++;           r = s[j];         }       }       vec.push_back(make_pair(cnt, make_pair(r, s)));     }     sort(vec.begin(), vec.end());     vector<pair<string, string>> v1;     vector<pair<string, string>> v2, v4, v5;     vector<pair<int, pair<char, string>>> v3;     for (i = 0; i < vec.size(); i++) {       if (i == vec.size() - 1) {         v3.push_back(vec[i]);         break;       }       if (vec[i].first == vec[i + 1].first) {         if (vec[i].second.first == vec[i + 1].second.first) {           v1.push_back(make_pair(vec[i].second.second, vec[i + 1].second.second));           i++;           continue;         } else {           v3.push_back(vec[i]);           continue;         }       } else {         v3.push_back(vec[i]);         continue;       }     }     sort(v3.begin(), v3.end());     for (i = 0; i < v3.size(); i++) {       if (i == v3.size() - 1) break;       if (v3[i].first == v3[i + 1].first) {         v2.push_back(make_pair(v3[i].second.second, v3[i + 1].second.second));         i++;       }     }     n1 = min(v1.size(), v2.size());     cnt = 0;     cnt = cnt + n1;     if (v1.size() > n1) {       cnt += (v1.size() - n1) / 2;     }     cout << cnt << endl;     for (i = 0; i < n1; i++) {       cout << v2[i].first <<     << v1[i].first << endl;       cout << v2[i].second <<     << v1[i].second << endl;     }     if (cnt > n1) {       for (i = n1; i < v1.size(); i++) {         if (v1.size() - 1 > i) {           cout << v1[i].first <<     << v1[i + 1].first << endl;           cout << v1[i].second <<     << v1[i + 1].second << endl;           i++;         }       }     }     return 0;   }   