a = list(input().split())
b = list(set(a))
if a.count(b[0]) > 1:
print(b[0])
else:
print(b[1])
(python)
a = list(input().split())
b = list(set(a))
if a.count(b[0]) > 1:
print(b[0])
else:
print(b[1])
(python)