#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct node {
	char data;
	struct node *left;
	struct node *right;
} Node;

Node *build_tree (char *pre, char *in, int n) {
	if (n <= 0) return NULL;
	
	Node *root = (Node *)malloc(sizeof(Node));
	root->data = pre[0];
	
	int idx = 0;
	for (int i = 0; i < n; i++) {
		if (in[i] == pre[0]) {
			idx = i;
			break;
		}
	}
	
	root->left = build_tree(pre + 1, in, idx);
	root->right = build_tree(pre + idx + 1, in + idx + 1, n - idx - 1);
    return root;
}

void post_order (Node *root) {
	if (root == NULL) return;
	post_order(root->left);
	post_order(root->right);
	printf("%c", root->data);
}

int main () {
	char pre[27];
	char in[27];
	while (scanf("%s", pre) != EOF) {
		scanf("%s", in);
		Node *root = build_tree(pre, in, strlen(pre));
		post_order(root);
		printf("\n");
	}
	
	return 0;
}