# No.123 カードシャッフル
N, M = [int(i) for i in input().split()]
A = [int(i) - 1 for i in input().split()]
cards = list((range(N)))

for i in range(M):
    cards = [cards[A[i]]] + cards[:A[i]] + cards[A[i] + 1:]

print(cards[0] + 1)