#include<iostream>
#include<cstdio>
#include<cctype>
#include<cstring>
#define gys mylove
using namespace std;
const int maxn=5010;
char a1[maxn],a2[maxn];
int dp[maxn][maxn],l1,l2;
inline void in(int &x)
{
    x=0;int f=1;char t=getchar();
    while(!isdigit(t)){if(t=='-')f=-1;t=getchar();}
    while(isdigit(t)){x=x*10+t-48;t=getchar();}
    x*=f;
}
inline void work(){
	scanf("%s%s",a1+1,a2+1);
	l1= strlen(a1+1),l2=strlen(a2+1);
	for(int i=1;i<=l1;i++){
		for(int j=1;j<=l2;j++){
		    if(a1[i]==a2[j]) dp[i][j]=dp[i-1][j-1]+1;
		    else dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
		}
	}
	printf("%d",dp[l1][l2]-1);
}
int Main(){
	freopen("lcslength.in","r",stdin);
	freopen("lcslength.out","w",stdout);
	work();
	return 0;
}
int main(){;}
int gys=Main();