from sys import stdin


def main():
    input = lambda: stdin.readline()[:-1]
    A, B, C = map(int, input().split())

    x = {0, 1, 2, 3} ^ {A, B, C}
    n = len(x)
    if n == 1:
        print(*x)
    elif n == 2:
        print(A ^ B ^ C)
    else:
        print(A)


main()