#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 k = n;
	int ans = 0;
	for (int i = n - 1; i >= 0; i--) {
		if (a[i] == k) {
			k--;
		} else ans++;
	}

	cout << ans << endl;
}