#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
char a[5001];
char b[5001];
int f[5001][5001];
int la,lb;
int main()
{
	freopen("lcslength.in","r",stdin);
	freopen("lcslength.out","w",stdout);
	scanf("%s%s",a+1,b+1);
	la=strlen(a+1)-1;
	lb=strlen(b+1)-1;
	for(int i=1;i<=la;i++)
	{
		for(int j=1;j<=lb;j++)
		{
			if(a[i]==b[j])
			{
				f[i][j]=max(max(f[i-1][j],f[i][j-1]),f[i-1][j-1]+1);
			}
			else
			{
				f[i][j]=max(f[i-1][j],f[i][j-1]);
			}
		}
	}
	printf("%d",f[la][lb]);
	return 0;
}