func_code_string: #include <bits/stdc++.h>   int pct(int x) { return __builtin_popcount(x); }   using namespace std;   char grid[101][101];   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     ;     int n, m;     char c;     cin >> n >> m >> c;     int row;     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         cin >> grid[i][j];       }     }     set<char> s;     long long ans = 0;     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         if (grid[i][j] != c && grid[i][j] !=  . ) {           if (i + 1 < n && grid[i + 1][j] == c && s.find(grid[i][j]) == s.end()) {             ans++;             s.insert(grid[i][j]);           } else if (i - 1 >= 0 && grid[i - 1][j] == c &&                      s.find(grid[i][j]) == s.end()) {             ans++;             s.insert(grid[i][j]);           } else if (j + 1 < m && grid[i][j + 1] == c &&                      s.find(grid[i][j]) == s.end()) {             ans++;             s.insert(grid[i][j]);           } else if (j - 1 >= 0 && grid[i][j - 1] == c &&                      s.find(grid[i][j]) == s.end()) {             ans++;             s.insert(grid[i][j]);           }         }       }     }     cout << ans << endl;     return 0;   }   