package main

import (
	"fmt"
)

func main() {
	var N int
	var arr [100005]int

	fmt.Scan(&N)
	for i := 0; i < N; i++ {
		fmt.Scan(&arr[i])
	}

	ret := 0
	x := 0
	y := N
	for i := N - 1; i >= 0; i-- {
		if y == arr[i] {
			y--
			x++
		}
	}
	ret = N - x

	fmt.Println(ret)
}