func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, i, j, x = 0;     char c[30][30] = {0};     scanf( %d n , &n);     for (i = 1; i <= n; i++) {       char temp[605] =   ;       cin.getline(temp, 605);       int length = strlen(temp);       for (j = 0; j < length; j++) {         c[0][temp[j] - 96] = 1;         if (j != length - 1) c[temp[j] - 96][temp[j + 1] - 96] = 1;       }     }     for (i = 0; i <= 26; i++) {       for (j = 1; j <= 26; j++) {         if (c[i][j] == 0 && i == 0) {           printf( %c n , j + 96);           x = 1;         } else if (c[i][j] == 0) {           printf( %c%c n , i + 96, j + 96);           x = 1;         }         if (x == 1) return 0;       }     }     return 0;   }   