from collections import deque

def main():
    N, M = map(int, input().split())
    A = tuple(map(int, input().split()))

    card = deque(range(1, N + 1))
    for i in A:
        x = card[i-1]
        card.remove(card[i-1])
        card.appendleft(x)

    print(card[0])

main()