#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
using namespace std;
const int maxn=5001;
char a[maxn],b[maxn];
int l1,l2,c[maxn][maxn];
int main()
{
	freopen("lcslength.in","r",stdin);
	freopen("lcslength.out","w",stdout);
	scanf("%s%s",a,b);
	l1=strlen(a);
	l2=strlen(b);
	for(int i=1;i<l1;i++)
	  for(int j=1;j<l2;j++)
	    if(a[i-1]==b[j-1])
	      c[i][j]=c[i-1][j-1]+1;
	    else c[i][j]=max(c[i-1][j],c[i][j-1]);
	printf("%d",c[l1-1][l2-1]);
	return 0;
}