#include <bits/stdc++.h>
using namespace std;
string a,b;
int n,m;
int main()
{
    cin >> a >> b;
    n = a.size();
    m = b.size();
    int dp[n+1][m+1];
    for(int i = 0; i <= n; i++)
        dp[i][0] = i;
    for(int i = 0; i <= m; i++)
        dp[0][i] = i;
    dp[0][0] = 0;
    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= m; j++)
        {
            if(a[i-1] == b[j-1])
                dp[i][j] = dp[i-1][j-1];
            else
            {
                dp[i][j] = 1 + min(dp[i-1][j],min(dp[i][j-1],dp[i-1][j-1]));
            }
        }
    }
    cout << dp[n][m];
    return 0;
}