import java.util.*;

class JengaSortFix2 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int max = sc.nextInt();
		int cnt = max - 1;
		ArrayList<Integer> nlist = new ArrayList<Integer>();
		nlist.add(sc.nextInt());
		for (int i = 0; i < max - 1; i++) {
			int next = sc.nextInt();
			if (next > JengaSortFix2.maxNum(nlist)) {
				if (nlist.contains(next - 1)) {
					cnt--;
				} else {
					cnt = max - 1;
				}
			nlist.add(next);
			}
		}
		System.out.println(cnt);
	}
	private static int maxNum(ArrayList<Integer> nlist) {
		int max = 0;
		for (Integer n : nlist) {
			int num = n.intValue();
			if (num > max) {
				max = num;
			}
		}
		return max;
	}
}