package yukicoder;
import java.util.Scanner;
public class Main{
	public static void main(String[] args)throws Exception{
		new Main().solve();
	}
	void solve(){
		Scanner sc=new Scanner (System.in);
		int n=sc.nextInt();
		int[] a=new int[n];
		for(int i=0;i<n;i++){
			a[i]=sc.nextInt();
		}
		int max=n;
		int count=0;
		for(int i=n-1;i>=0;i--){
			if(max==a[i])max--;
			else count++;
		}
		System.out.println(count);
	}
}