func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 5e3 + 1;   char a[N], b[N];   int f[N][N];   int res;   int n, m;   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     cin >> n >> m;     for (int i = 1; i <= n; i++) cin >> a[i];     for (int i = 1; i <= m; i++) cin >> b[i];     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= m; j++) {         if (a[i] == b[j]) {           f[i][j] = f[i - 1][j - 1] + 2;         }         f[i][j] = max(f[i][j], max(f[i - 1][j], f[i][j - 1]) - 1);         res = max(res, f[i][j]);       }     }     cout << res;   }   