#include <bits/stdc++.h>
using namespace std;
 
string t[101][101];
 
string LCS(string a, string b, int n , int m){
	for(int i=0 ; i<n+1 ; i++){
		for(int j=0 ; j<m+1 ; j++){
			if(i==0||j==0){
				t[i][j] = "";
			}
			if(a[i-1]==b[j-1]){
				t[i][j] = a[i-1]+t[i-1][j-1];
			}else{
				t[i][j] = max(t[i-1][j] , t[i][j-1]);
			}
		}
	}
	return t[n][m];
}
 
int main() {
	string a;
	string b;
	cin>>a;
	cin>>b;
	int n = a.length();
	int m = b.length();
	cout<<LCS(a,b,n,m);
	return 0;
}

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