#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];
	}
	for (int i = n - 1;i >= 0;i--) {
		if (a[i] == n) {
			n--;
		}
	}
	cout << n << endl;

	return 0;
}