func_code_string: #include <bits/stdc++.h>   using namespace std;   char s[120][120];   int n, m;   int main() {     int i, j, k, res = 30, now = 0;     string ss =   ;     scanf( %d%d , &n, &m);     for (i = 0; i < n; i++) scanf( %s , s[i]);     for (i = 0; i < n; i++) {       for (j = 0; j < m; j++) {         char c = s[i][j];         int f = 0;         for (k = 0; k < n; k++) {           if (i == k) continue;           if (s[k][j] == c) f = 1;         }         for (k = 0; k < m; k++) {           if (j == k) continue;           if (s[i][k] == c) f = 1;         }         if (!f) ss += c;       }     }     cout << ss << endl;     return 0;   }   