Codeup 1411 - 빠진 카드


n = int(input())
cards = []
miss = []
for i in range(1, n+1):
    cards.append(i)
for i in range(0, n-1):
    num = int(input())
    miss.append(num)
for card in miss:
    cards.remove(card)
print(cards[0])