#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#include<stack>
#include<queue>
#include<cstring>
#include<deque>
#define maxn 5010
#define itn int
#define xlm mylove
using namespace std;
typedef long long LL;typedef unsigned long long ULL;
char a[maxn],b[maxn];
int f[maxn][maxn],len1,len2;
inline void in(){
//	freopen("a.in","r",stdin);
	freopen("lcslength.in","r",stdin);
	freopen("lcslength.out","w",stdout);
	scanf("%s\n",a);scanf("%s",b);
}
inline void dp(){
	for (int i=0;i<len1;i++){
		for (int j=0;j<len2;j++){
			if (a[i]==b[j]){
				f[i+1][j+1]=f[i][j]+1;
			}
			else {
				f[i+1][j+1]=max(f[i][j+1],f[i+1][j]);
			}
		}
	}
}
inline void p(){
	printf("%d",f[len1][len2]-1);
	fclose(stdin);fclose(stdout);
}
int Main(){
	in();
	len1=strlen(a),len2=strlen(b);
	dp();
	p();
	return 0;
}
int main(){;}
int xlm=Main();