Shared code

/* 777 */
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define FAST_IO ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

const int MOD = 1e9 + 7;
int n, m;
int dp[5001][5001];
string a, b;

void solve() {
    cin >> a >> b;
    n = a.size();
    m = b.size();
    
    // base case
    for (int i = 0 ; i < n ; ++i) dp[i][m] = n - i;
    for (int j = 0 ; j < m ; ++j) dp[n][j] = m - j;

    for (int i = n - 1 ; i >= 0 ; --i) {
        for (int j = m - 1 ; j >= 0 ; --j) {
            dp[i][j] = (a[i] != b[j]) + dp[i + 1][j + 1]; // edit
            dp[i][j] = min(dp[i][j], 1 + dp[i + 1][j]); // remove
            dp[i][j] = min(dp[i][j], 1 + dp[i][j + 1]); // add
        }
    }

    cout << dp[0][0];
}

int32_t main() {
    FAST_IO
    solve();
}