N, M = map(int, input().split())
l = list(map(int, input().split()))
d = [] 
for i in range(1, N + 1):
    d.append(i)

s = 0
for i in l:
    s = d[i - 1]
    d.pop(i - 1)
    d.insert(0, s)
    

print(d[0])