import java.util.*;
import java.io.*;
class prob365
{
    public static void main(String args[])throws IOException
    {
	BufferedReader sc=new BufferedReader(new InputStreamReader(System.in));
	int n=Integer.parseInt(sc.readLine());
	String s[]=sc.readLine().split(" ");
	int a[]=new int[n];
	for(int i=0;i<n;i++)a[i]=Integer.parseInt(s[i]);
	int ans=n;
	int target=n;
	for(int i=n-1;i>=0;i--)
	    {
		if(target==a[i])
		    {
			ans--;
			target--;
		    }
	    }
	System.out.println(ans);
    }
}