# coding: utf-8
# Your code here!

N = int(input())
a = list(map(int,input().split()))
#print(a)
m = len(a)
orderCount = 1 # 順番に並んでる個数
for i in range(2,m+1)[::-1]:
    if a.index(i-1) > a.index(i):
        break
    else:
        orderCount += 1

print(m-orderCount)