#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cmath>
#include <stack>
#include <queue>
#include <cctype>
#include <stdio.h>
#include <map>
#include <string.h>
#include <utility>

typedef long long ll;
using namespace std;

typedef pair<int, int> P;

ll genga[100001];
int main() {

	int n;
	cin >> n;

	int cp=0;

	int last =n;
	for (int i = 0; i < n; i++) {
		ll tmp = 0;
		cin >> tmp;

		genga[i] = tmp;
	}
	for(int j=n-1; j>=0; j--){
		if(genga[j] == last){
			cp++;
			last--;
		}
	}


	cout<<n-cp<<endl;

	return 0;
}