#! python3

list1 = input()
list2 = input()

index1 = 0
index2 = 0

result = ""

while index1 + index2 < len(list1) + len(list2):
    if index1 == len(list1):
        result = result + list2[index2]
        index2 += 1
    elif index2 == len(list2):
        result = result + list1[index1]
        index1 += 1
    elif list1[index1] < list2[index2]:
        result = result + list1[index1]
        index1 += 1
    else:
        result = result + list2[index2]
        index2 += 1

print(result)