N, M = map(int, input().split())
A = list(map(int, input().split()))
stack = [i + 1 for i in range(N)]
for a in A:
    a -= 1
    ns = []
    for i in range(N):
        if i == a:
            continue
        ns.append(stack[i])
    ns = [stack[a]] + ns
    stack = ns
print(stack[0])