#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    //ifstream fin("be.in");
    int n,k;
    bool a[100001];
    cin>>n>>k;
    for (int i=1;i<=n;i++)
    {
        cin>>a[i];
    }
    int db=0, x=0,j;
    for (int i=1;i<n-k;i++)
    {
        x=0;
        j=i+1;
        while (x!=k and j<=n)
        {
            if (a[j])
                x++;
            j++;
        }
        if (x==k)
            db++;
    }
    cout<<db;
    return 0;
}