# -*- coding: utf-8 -*-

import sys, copy, math, itertools

from copy import *

from collections import deque

import numpy as np

from heapq import *

from bisect import *

import scipy as sp



A, B, C = list( map(int, input().split() ) )



if A==B: print(C)

if B==C: print(A)

if C==A: print(B)
# -*- coding: utf-8 -*-

import sys, copy, math, itertools

from copy import *

from collections import deque

import numpy as np

from heapq import *

from bisect import *

import scipy as sp

#from scipy.optimize import linprog

from scipy import ceil, ifft

from scipy.fftpack import fft



A, B, C = list( map(int, input().split() ) )



if A==B: print(C)

if B==C: print(A)

if C==A: print(B)
# -*- coding: utf-8 -*-
import sys, copy, math, itertools
from copy import *
from collections import deque
import numpy as np
from heapq import *
from bisect import *
import scipy as sp

A, B, C = list(map(int, input().split()))
if A == B:
    print(C)
if B == C:
    print(A)
if C == A:
    print(B)

# -*- coding: utf-8 -*-
import sys, copy, math, itertools
from copy import *
from collections import deque
import numpy as np
from heapq import *
from bisect import *
import scipy as sp

# from scipy.optimize import linprog
from scipy import ceil, ifft
from scipy.fftpack import fft

A, B, C = list(map(int, input().split()))
if A == B:
    print(C)
if B == C:
    print(A)
if C == A:
    print(B)

+# from scipy.optimize import linprog +from scipy import ceil, ifft +from scipy.fftpack import fft +