# Get the input
leftLane = input().split(' ')
rightLane = input().split(' ')
# Solve the problem
zipLane = []
a = 0
while a < len(leftLane):
    if leftLane[a] != None:
        zipLane.append(leftLane[a])
    if a < len(rightLane):
        zipLane.append(rightLane[a])
    a += 1
while a < len(rightLane):
    zipLane.append(rightLane[a])
    a += 1
carString = ''
for i in zipLane:
    if carString == '':
        carString = carString + i
    else:
        carString = carString + " " + i
# Print the result
print(carString)