#include <bits/stdc++.h>
using namespace std;
int main() {
    string a, b, c = "";
    cin >> a >> b;
    int i, j, x = a.size(), y = b.size();
    int dp[x+1][y+1];
    memset(dp, 0, sizeof(dp));
    for(i = 1; i <= x; ++i)
        for(j = 1; j <= y; ++j) {
            if(a[i-1] == b[j-1]) dp[i][j] = dp[i-1][j-1] + 1;
            else dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
        }
    while(x && y) {
        if(a[x-1] == b[y-1]) c = a[x-1] + c, --x, --y;
        else if(dp[x][y] == dp[x-1][y]) --x;
        else --y;
    }
    cout << c;
    return 0;
}