#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>

using namespace std;

int main() {
	int n;

	cin >> n;
	vector<int> a(n, 0);
	for (int i = 0; i < n; i++) {
		cin >> a[i];
	}

	int ans = 0;
	int num = n;
	for (int i = n - 1; i >= 0; i--) {
		if (a[i] == num) {
			num--;
		} else {
			ans++;
		}
	}
	cout << ans << endl;
	return 0;
}