#include<bits/stdc++.h>
using namespace std;
string A , B ;
int d[2001][2001];
int main()
{
	cin>>A>>B;
	for(int i = 1 ; i <= A.length() ; i++ )
	{
		for(int j = 1 ; j <= B.length() ; j++ )
		{
			if(A[i-1] == B[j-1])d[i][j] = min(min(d[i-1][j-1] ,d[i-1][j]+1 ) ,min(d[i][j-1] +1 ,  d[i-1][j]+1 ));
			else d[i][j] = min(min(d[i-1][j-1]+1 ,d[i-1][j]+1 ) ,min(d[i][j-1] +1 ,  d[i-1][j]+1 ));
		}
	}
	cout<<d[A.length()][B.length()];
	return 0;//华丽结束 
}