l = input().split()
m = int(l[1])
n = int(l[0])
a = list(map(int, input().split()))
c = [i for i in range(n)]
for i in range(m):
  c.insert(0, c[a[i] - 1])
  del c[a[i] - 1]
print(c[0] + 1)