N,M = map(int,input().split())
shuffle_card = list(map(int,input().split()))
N = list(range(1,N+1))

for i in range(M):
        shuffle_num = shuffle_card[i]
        work = N[shuffle_num - 1]
        del N[shuffle_num - 1]
        N.insert(0,work)
        
print(N[0])