#include <iostream>
#include <vector>

using namespace std;

int main()
{
	int N;
	vector<int> a;
	
	cin >> N;
	for (int i = 0, x; i < N; ++i) {
		cin >> x;
		a.push_back(x);
	}
	
	for (int i = N-1; i >= 0; --i) {
		if (a[i] == N) --N;
	}
	
	cout << N << endl;
	
	return 0;
}