func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 5010 + 10;   const int mod = 1e9 + 7;   char s[N];   char t[N];   int d[N][N];   int main() {     int n, m;     cin >> n >> m;     scanf( %s%s , s + 1, t + 1);     int ans = 0;     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= m; j++) {         d[i][j] = max(d[i - 1][j], d[i][j - 1]) - 1;         if (s[i] == t[j]) {           d[i][j] = d[i - 1][j - 1] + 2;           d[i][j] = max(d[i][j], 2);         }         ans = max(ans, d[i][j]);       }     }     cout << ans << endl;     return 0;   }   