#include<cmath>
#include<cstring>
#include<algorithm>
#include<cstdio>
#include<iostream>
using namespace std;
const int maxn=5200;
int f[maxn][maxn];
string s1,s2;
int main(){
	freopen("lcslength.in","r",stdin);
	freopen("lcslength.out","w",stdout);
	cin>>s1>>s2;
	int len1=s1.length()-1,len2=s2.length()-1;
	for(int i=len1;i>0;i--)s1[i]=s1[i-1];
	for(int i=len2;i>0;i--)s2[i]=s2[i-1];
	for(int i=1;i<=len1;i++){
		for(int j=1;j<=len2;j++){
			if(s1[i]==s2[j])f[i][j]=f[i-1][j-1]+1;
			else f[i][j]=max(f[i-1][j],f[i][j-1]);
		}
	}
	printf("%d",f[len1][len2]);
	return 0;
}