#include<bits/stdc++.h>
using namespace std;
string s1,s2;
int a[2005][2005];
int dp[2005][2005];
int main(){
	cin>>s1>>s2;
	int len1=s1.size();
	int len2=s2.size();
	for(int i=0;i<len1;++i){
		a[0][i+1]=s1[i]-'A'+1;
		dp[1][i+1]=i+1;
	}
	for(int j=0;j<len2;++j){
		a[j+1][0]=s2[j]-'A'+1;
		dp[j+1][1]=j+1;
	}
	for(int i=2;i<=len2;++i){
		for(int j=2;j<=len1;++j){
			if(a[0][i]==a[j][0]){
				dp[i][j]=dp[i-1][j-1];
			}
			else dp[i][j]=min(dp[i-1][j-1]+1 , min(dp[i-1][j]+1,dp[i][j-1]+1) );
		}
	}
	
	/*
	for(int i=1;i<len2+1;++i){
		for(int j=1;j<len1+1;++j){
			cout<<dp[i][j]<<" ";
		}
		cout<<"\n";
	}
	
	sfdqxbw
	gfdgw
	*/
	cout<<dp[len2][len1];
	return 0;
}