N,M = map(int, raw_input().split())
A = map(int, raw_input().split())
pos = [0] * (N + 1)
for i in range(1, N + 1):
    pos[i] = i

for x in A:
    tmp = pos[x]
    for y in reversed(range(2, x + 1)):
        pos[y] = pos[y - 1]
    pos[1] = tmp
print pos[1]