1791

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    ifstream fin("input.txt");
    ofstream fout("output.txt");

    string strA, strB;
    fin >> strA >> strB;
    int nA = strA.size(), nB = strB.size();
    strA = " " + strA; strB = " " + strB;
    vector<vector<int>> dp(nA+1, vector<int>(nB+1));
    for (int i = 0; i <= nA; i++) dp[i][0] = i;
    for (int i = 0; i <= nB; i++) dp[0][i] = i;
    for (int curA = 1; curA <= nA; curA++)
        for (int curB = 1; curB <= nB; curB++) {
            if (strA[curA] == strB[curB])
                dp[curA][curB] = dp[curA - 1][curB - 1];
            else
                dp[curA][curB] = min(dp[curA - 1][curB - 1], min(dp[curA][curB - 1], dp[curA - 1][curB])) + 1;
        }
    fout << dp[nA][nB] << endl;

    fin.close();
    fout.close();
    return 0;
}