#include <iostream>
using namespace std;

int main(){
	int ans = 0,n;
	cin >> n;
	int a[n];
	for(int i = 0;i < n;i++) cin >> a[i];
	for(int i = n - 1;i--;) if(a[i] > a[i + 1]) ans++;
	cout << ans << endl;
}