#include <bits/stdc++.h>

using namespace std;

const int N = 2010;
char a[N], b[N];
int al, bl;
int f[N][N];

int main() {
    cin >> a + 1 >> b + 1;
    al = strlen(a + 1), bl = strlen(b + 1);

    //初始化
    for (int i = 1; i <= bl; i++) f[0][i] = i;
    for (int i = 1; i <= al; i++) f[i][0] = i;

    for (int i = 1; i <= al; i++)
        for (int j = 1; j <= bl; j++) {
            //增加删除
            f[i][j] = min(f[i - 1][j] + 1, f[i][j - 1] + 1);
            //修改
            if (a[i] == b[j])
                f[i][j] = min(f[i][j], f[i - 1][j - 1]);
            else
                f[i][j] = min(f[i][j], f[i - 1][j - 1] + 1);
        }

    printf("%d\n", f[al][bl]);

    return 0;
}