#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

char s1[100000];
char s2[100000];
char s[20][100000];

int main()
{
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);


	int i=0, n=0, j=0, k=0, g=0;

	int a, b, sum;

	strcpy(s[0], "{}");
	strcpy(s[1], "{{}}");


	for(i=2;i<16;i++)
	{
		n = strlen(s[i-1]);

		for(j=0; j < n-1; j++)
		{
			s[i][j]=s[i-1][j];
			k=j+1;
		}

		s[i][k]=',';
		k++;
		for(j=0; j < n; j++)
			s[i][j+k]=s[i-1][j];
		s[i][k+j]='}';

		//cout << s[i] << endl << endl;
		
	}

	cin >> s1;
	cin >> s2;
	for(i=0;i<16;i++)
	{
		if(!strcmp(s[i], s1)) a=i;
		if(!strcmp(s[i], s2)) b=i;
	}

	sum = a+b;

	for(i=0;i<16;i++)
		if(sum==i)
			cout << s[i];

	//cout << s[15];


	return 0;
}