a = input()
b = input()
c = a + b
li=[]
for i in range (0,25):
    li.append(0)
for i in c:
    li[ord(i)-97] += 1 
    if li[ord(i)-97] == 1:
        print(i,end='')
    
/**************************************************************
	Problem: 1105
	User: admin
	Language: Python
	Result: Accepted
	Time:95 ms
	Memory:34480 kb
****************************************************************/