N, M = map(int, input().split())
A = list(map(int, input().split()))

place = [i for i in range(N)]

for a in A:
    a -= 1
    memo = place[a]
    for i in range(a, 0, -1):
        place[i] = place[i - 1]
    place[0] = memo

ans = place[0] + 1
print(ans)