#include <iostream>

#include <cstring>

#include <cstdio>

using namespace std;

char qianxu[],  zhongxu[];

void Print_(char* qian, char* zhong, int len){

    char ch = *qian;//根节点

    if( len ==  ) return ;

    int i=;

    for(; i<len; i++ ){

        if( zhong[i] == *qian )

            break ;

    }

    Print_(qian+, zhong, i);//左子树

    Print_(qian+i+, zhong+i+, len-(i+) ) ;//右子树

    printf("%c",ch);

}

int main(){

    while(~scanf("%s%s",qianxu,zhongxu) ){

        Print_(qianxu, zhongxu, strlen(qianxu));

        printf("\n");

    }

    return ;

}