import java.util.Scanner;

public class Main {

	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[] nums = new int[n];
		int[] pos  = new int[n + 1];

		for (int i = 0; i < n; i++) {
			nums[i] = sc.nextInt();
			pos[nums[i]] = i;
		}

		System.out.println(solve(nums, pos));

		sc.close();
	}

	public static int solve (int[] nums, int[] pos) {
		for (int i = nums.length; i > 1; i--)
			if (pos[i] < pos[i - 1]) return i - 1;
		return 0;
	}

}