#include<bits/stdc++.h>
using namespace std;
int dp[3005][3005];
string s1,s2;
int main(){
    cin>>s1>>s2;
    int l1=s1.size(),l2=s2.size();
    for(int i=0;i<l1;i++)
        for(int j=0;j<l2;j++){
        dp[i][0]=i,dp[0][j]=j;
        if(s1[i]==s2[j]) dp[i][j]=dp[i-1][j-1];
        else 
            dp[i][j]=min(dp[i-1][j],min(dp[i][j-1],dp[i-1][j-1]))+1;
    }
    cout<<dp[l1-1][l2-1];
    return 0;
}