#include <iostream>
#include <cstdio>

using namespace std;

const int N = 2010;

int f[N][N];
string a, b;

int main() {
    freopen("expr.in", "r", stdin);
    freopen("expr.out", "w", stdout);

    cin >> a >> b;
    int n = a.size();
    a = ' ' + a;
    int m = b.size();
    b = ' ' + b;

    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];
            } else {
                f[i][j] = min(f[i - 1][j] + 1, min(f[i][j - 1] + 1, f[i - 1][j - 1] + 1));
            }
        }
    }

    printf("%d\n", f[n][m]);
    
    return 0;
}