func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long INF = 1000000000 + 7;   const double esp = 1e-13;   const double pi = 3.141592653589;   int n, m, f[100 + 10][100 + 10];   char a[100 + 10][100 + 10];   int main() {     ios ::sync_with_stdio(false);     cin >> n >> m;     for (int i = (1), _b = (n); i <= _b; i++)       for (int j = (1), _b = (m); j <= _b; j++) cin >> a[i][j];     memset(f, 0, sizeof(f));     for (int i = (1), _b = (n); i <= _b; i++)       for (int j = (1), _b = (m); j <= _b; j++) {         for (int k = (1), _b = (m); k <= _b; k++)           if (a[i][j] == a[i][k] && j != k) f[i][j] = 1, f[i][k] = 1;         for (int k = (1), _b = (n); k <= _b; k++)           if (a[i][j] == a[k][j] && i != k) f[i][j] = 1, f[k][j] = 1;       }     for (int i = (1), _b = (n); i <= _b; i++)       for (int j = (1), _b = (m); j <= _b; j++)         if (f[i][j] == 0) cout << a[i][j];   }   