#include <iostream>
using namespace std;

int main(){
    int ans = 0,n;
    cin >> n;
    int now = n,a[n];
    for(int i = 0;i < n;i++) cin >> a[i];
    for(int i = n;i--;) if(a[i] == now) now--;
    if(now != a[0] - 1) ans++;
	for(int i = n - 1;i--;) if(a[i] > a[i + 1]) ans++;
	cout << ans << endl;
}