#include<bits/stdc++.h>
using namespace std;
int dp[105][105];

int main(){
    string s1,s2;
    cin >> s1 >> s2;
    int len1 = s1.size();
    int len2 = s2.size();
    memset(dp,0,sizeof(dp));
    int ans = 0;
    int end = 0;
    for(int i = 1;i <= len1;i++){
        for(int j = 1;j <= len2;j++){
            if(s1[i - 1] == s2[j - 1]){
            dp[i][j] = dp[i - 1][j - 1] + 1;
            }else{
//                dp[i][j] = max(dp[i - 1][j],dp[i][j - 1]);
                 dp[i][j] = 0;
            }
            if(ans < dp[i][j]){
                ans = dp[i][j];
                end = j - 1;
            }
        }
    }
//    cout << dp[6][6];
    string str = "";
    for(int i = end,k =0;k < ans;k++){
        str += s2[i - k];
    }
    reverse(str.begin(),str.end());
    cout << str << endl;
}