func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, m;   char my_array[50][50];   bool visited[50][50];   bool dfs(int i, int j, int c_i, int c_j) {     if (visited[i][j]) {       return true;     }     visited[i][j] = true;     char col = my_array[i][j];     bool res = false;     if (i > 0 && col == my_array[i - 1][j] && c_i != i - 1) {       res |= dfs(i - 1, j, i, j);     }     if (j > 0 && col == my_array[i][j - 1] && c_j != j - 1) {       res |= dfs(i, j - 1, i, j);     }     if (i < n - 1 && col == my_array[i + 1][j] && c_i != i + 1) {       res |= dfs(i + 1, j, i, j);     }     if (j < m - 1 && col == my_array[i][j + 1] && c_j != j + 1) {       res |= dfs(i, j + 1, i, j);     }     return res;   }   int main(int argc, const char* argv[]) {     cin >> n >> m;     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         cin >> my_array[i][j];       }     }     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         if (!visited[i][j] && dfs(i, j, -1, -1)) {           cout <<  Yes ;           return 0;         }       }     }     cout <<  No ;     return 0;   }   