import fileinput
file = fileinput.input()
for line in file:
  nums = list(map(int, line.split(" ")))
  amnt = sum(nums)
  for number in nums:
    if amnt-number==number:
      print(number)
      break

b4b4769913a61083133ac25690cc2d5a2afbe513
<mask token>

<mask token>
for line in file:
    nums = list(map(int, line.split(' ')))
    amnt = sum(nums)
    for number in nums:
        if amnt - number == number:
            print(number)
            break

<mask token>
file = fileinput.input()
for line in file:
    nums = list(map(int, line.split(' ')))
    amnt = sum(nums)
    for number in nums:
        if amnt - number == number:
            print(number)
            break

import fileinput
file = fileinput.input()
for line in file:
    nums = list(map(int, line.split(' ')))
    amnt = sum(nums)
    for number in nums:
        if amnt - number == number:
            print(number)
            break

import fileinput
file = fileinput.input()
for line in file:
  nums = list(map(int, line.split(" ")))
  amnt = sum(nums)
  for number in nums:
    if amnt-number==number:
      print(number)
      break
