using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Text;
using System.Text.RegularExpressions;
using System.Linq;

class Magatro
{
    static void Main()
    {
        int N = int.Parse(Console.ReadLine());
        int[] a = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        int max = N;
        int cnt = 0;
        for(int i = N - 1; i >= 0; i--)
        {
            if (a[i] == max)
            {
                max--;
                cnt++;
            }
        }
        Console.WriteLine(N-cnt);
    }

}