import java.io.BufferedInputStream;
import java.util.Scanner;
public class Main {
	static final long C =  1000000007;
	static final int CY = 1000000000;
	StringBuilder sb;

	public void calc() {
		sb = new StringBuilder();
		BufferedInputStream bs = new BufferedInputStream(System.in);

		Scanner sc = new Scanner(bs);

		int n = sc.nextInt();

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


		long ans = 0;
		int bef = n+1;
		for (int i=n-1; i >= 0; i--) {
			if (bef-1 != a[i]) {
				ans++;
			}else {
				bef = a[i];
			}
		}




		System.out.println(ans);
	}

	public static void main(String[] args) {
		Main main = new Main();
		main.calc();

	}
}