#!/usr/bin/env python
#coding:utf8


def read():
    raw_input()
    return map(int, raw_input().split())


def work(vList):
    cur = len(vList)
    ans = 0
    
    for v in vList[::-1]:
        if v == cur:
            cur -= 1
        else:
            ans += 1
    
    print ans


if __name__ == "__main__":
    work(read())