#include<bits/stdc++.h>
using namespace std;

int main(){
	int n;
	cin >> n;
	vector<int> a(n);
	for(int i = 0; i < n; i++){
		cin >> a[i];
	}
	
	int count = 0;
	int b = n;
	
	for(int i = n - 1; i >= 0; i--){
		if(a[i] == b){
			b--;
		}else{
			count++;
		}
	}
	cout << count << endl;
}