#include<bits/stdc++.h>
using namespace std;
int n,m,b[1000010],s,k;
int main(){
	cin>>n>>k;
	for(int i=1;i<=n;i++){
		cin>>m;
		b[i]=b[i-1]+m;
	}
	for(int i=1;i+k-1<=n;i++){
		if(k-b[i+k-1]+b[i-1]>b[i+k-1]-b[i-1]){
			s++;
		}
	}
	cout<<s;
    return 0;
}