#include <iostream>
#include <cmath>
#include <string>
#include <vector>
#include <map>
#include <list>
#include <deque>
#include <algorithm>

using namespace std;

int main() {
	vector<int> a;
	int n;
	cin >> n;

	for (int i = 0; i < n; i++) {
		int tmp;
		cin >> tmp;
		a.push_back(tmp);
	}

	int ans = 0;
	for (int i = n-1; i >-1; i--) {

		if (i != 0) {
			if (a[i - 1] > a[i]) {
				ans++;
			}
		}
	}

	cout << ans << endl;
	return 0;
}