#include <iostream>
#include <vector>
#include <locale>
#include <cstring>


using namespace std;

int min(int a, int b, int c) {
    int min = a;
    if (b < min) min = b;
    if (c < min) min = c;
    return min;
}

int different(int a, int b) {
    if (a != b) return 1;
    else return 0;
}

int main() {

    setlocale(LC_ALL, "Rus");


    string S1;
    string S2;
    cin >> S1;
    cin >> S2;



    size_t m = S2.size() + 1;
    size_t n = S1.size() + 1;

    vector<vector<int>> D(m);

    for (size_t i = 0; i < m; i++) D[i].resize(n);
    for (size_t j = 0; j < n; j++) D[0][j] = j;
    for (size_t k = 0; k < m; k++) D[k][0] = k;

    for (size_t i = 1; i < m; i++) {

        for (size_t j = 1; j < n; j++) {
            D[i][j] = min(D[i - 1][j - 1] + different(S2[j - 1], S1[i - 1]), D[i - 1][j] + 1, D[i][j - 1] + 1);
        }
    }

    cout << endl << D[m - 1][n - 1];

    return 0;
}