#include<iostream>
#include<vector>
using namespace std;
int solve(string s1,string s2,int n,int m){
    if(n==0){
        return m;
    }
    if(m==0){
        return n;
    }
    if(s1[n-1]==s2[m-1]){
        return 0;
    }
    return 1+min(
        solve(s1,s2,n,m-1),
        solve(s1,s2,n-1,m),
        solve(s1,s2,n-1,m-1)
        );
}
int main(){
    string s1,s2;
    cin>>s1>>s2;
    cout<<solve(s1,s2,s1.length,s2.length);
    return 0;
}