package main

import . "fmt"

func main() {
	var n int
	Scan(&n)
	a := make([]int, n)
	for i := range a {
		Scan(&a[i])
		a[i]--
	}
	ans := 0
	for i := range a {
		if a[i] == i {
			continue
		}
		ans++
		for j := range a {
			if a[j] == i {
				a[i], a[j] = a[j], a[i]
				break
			}
		}
	}
	Println(ans)
}