n,m = map(int,input().split())
a = [i+1 for i in range(n)]
pick_list = input().split()
for i in range(m):
	pick = int(pick_list[i])-1
	k = a[0]
	a[0] = a[pick]
	for j in range(pick):
		l = a[j+1]
		a[j+1] = k
		k = l
print(a[0])