package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func main() {
	var n int
	_, _ = fmt.Scan(&n)

	bs := bufio.NewScanner(os.Stdin)
	bs.Split(bufio.ScanWords)

	nums := make(map[int]int, 0) // 数字がどこにあるか
	for i := 0; i < n; i++ {
		bs.Scan()
		a, _ := strconv.Atoi(bs.Text())
		nums[a] = i
	}
	// fmt.Println(nums)

	cnt := 0
	fix := 0
	for {
		end := true
		for i := n - fix; i > 1; i-- {
			if nums[i] > nums[i-1] {
				fix++
			} else {
				end = false
				cnt++
				for j := 1; j <= n; j++ {
					if nums[j] < nums[i-1] {
						nums[j]++
					}
				}
				nums[i-1] = 0
				// fmt.Println(cnt, fix, nums)
			}
		}
		if end {
			break
		}
	}

	fmt.Println(cnt)
}