P1317

#include <bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin>>n;
    int a[n+5];
    for(int i = 1;i<=n;i++){
        cin>>a[i];
    }
    int i = 2,x;
    int sum = 0;
    while(i<n-1){
        if(a[i]>a[i+1]){
            x = a[i+1];
            i += 2;
            while(x>=a[i]){
                i++;
            }
            sum++;
        }else{
            i++;
        }
    }
    cout<<sum;
    return 0;
}