#include <iostream>
#include <vector>
#include <cstring>
using namespace std;
string s1, s2;
int dp[5005][5005];

int main() {
    cin >> s1 >> s2;
    int n = (int) s1.size();
    int m = (int) s2.size();

    for(int i = 0; i <= n; i++) {
        for(int j = 0; j <= m; j++) {
            dp[i][j] = 2e9;
        }
    }
    for(int i = 0; i <= n; i++) {
        for(int j = 0; j <= m; j++) {
            if(i == 0) {
                dp[i][j] = j;
                continue;
            }
            if(j == 0) {
                dp[i][j] = i;
                continue;
            }
            if(s1[i - 1] == s2[j - 1]) {
                dp[i][j] = min(dp[i][j], dp[i - 1][j - 1]);
            }
            dp[i][j] = min(dp[i][j], dp[i - 1][j] + 1);
            dp[i][j] = min(dp[i][j], dp[i][j - 1] + 1);
            dp[i][j] = min(dp[i][j], dp[i - 1][j - 1] + 1);
        }
    }
    cout << dp[n][m] << endl;
    return 0;
}