#include<iostream>
#include<algorith>
using namespace std;
int main(){
    string s1,s2;
    cin>>s1>>s2;
    int len1 = s1.length();
    int len2 = s2.length();
    vector<vector<int>>lcs(len1+1,vector<int>(len2+1,0));
    for(int i=1; i<len1; i++){
        for(int j=1;j <len2; j++){
            if(s1[i] == s2[j]){
                lcs[i][j] = 1+lcs[i-1][j-1];
            }
            else{
                lcs[i][j] = max(lcs[i-1][j],lcs[i][j-1]);
            }
        }
    }
    cout<<lcs[len1-1][len2-1]
}