import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		for (int i = 0; i < n; i++) {
		    arr[i] = sc.nextInt();
		}
		int count = n;
		int num = n;
		for (int i = n - 1; i >= 0; i--) {
		    if (arr[i] == num) {
		        count--;
		        num--;
		    }
		}
		System.out.println(count);
	}
}