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

int main() {
	int N, A[100000];
	cin >> 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;
}