#include <iostream>
#include<cstring>
using namespace std;

const int N = 1010;
int f[N][N];
char a[N], b[N];
int main() {
    cin >> a + 1;
    cin >> b + 1;
    int n = strlen(a + 1), m = strlen(b + 1);
    for(int i = 0; i <= n; i ++) f[i][0] = i;
    for(int i = 0; i <= m; i ++) f[0][i] = i;
    for(int i = 1; i <= n; i ++)
        for(int j = 1; j <= m; j ++){
            f[i][j] = min(f[i][j - 1] + 1, f[i - 1][j] + 1);
            if(a[i] == b[j]) f[i][j] = min(f[i][j], f[i - 1][j - 1]);
            else f[i][j] = min(f[i - 1][j - 1] + 1, f[i][j]);
        }
    cout << f[n][m] << endl;
}