func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, m;     cin >> n >> m;     pair<char, bool> ar[100][100];     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         cin >> ar[i][j].first;         ar[i][j].second = false;       }     }     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         for (int k = 0; k < m; k++) {           if (k == j) continue;           if (ar[i][j].first == ar[i][k].first) {             ar[i][j].second = true;             ar[i][k].second = true;           }         }         for (int k = 0; k < n; k++) {           if (k == i) continue;           if (ar[i][j].first == ar[k][j].first) {             ar[i][j].second = true;             ar[k][j].second = true;           }         }       }     }     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         if (ar[i][j].second == false) cout << ar[i][j].first;       }     }     cout << endl;     return 0;   }   