a,b,c = map(int, input().split())
mn = [a,b,c]
group = set([a,b,c])
vari = list(group)
length = len(group)
if length == 1: print(a)
elif length == 2:
    if mn.count(vari[0]) > mn.count(vari[1]):
        print(vari[1])
    else: print(vari[0])
else:
    ku = {0,1,2,3}
    print(*(ku-group))