#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cmath>
#include <stdio.h>
#include <string.h>
#include <iomanip>
#include <stack>
#include <unordered_map>

using namespace std;
#define all(v) (v.begin()), (v.end())

void fast_io()
{
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
}

int main()
{
    fast_io();
    int n, k;
    cin >> n >> k;
    int a[n];
    for (int i = 0; i < n; i++){
        cin >> a[i];
    }

    int res = 0;
    unordered_map<int, int> countMap;
    for (int i = 0; i < n; i++){
        int counter = 0;
        int sum = 0;

        while (i+k-1 < n && counter < k){
            sum += a[i+counter];
            counter++;
        }
        if (!sum) break; // Idea
        
        if (!countMap.count(sum) && sum){
            countMap[sum] = 1;
            //cout << sum << endl;
            res++;
        }
    }
    cout << res << endl;
}