#include <bits/stdc++.h>
using namespace std;
 
int main() {
	int n,k;
	cin>>n>>k;
 
	vector<int> numbers(n);
 
	for(auto& number: numbers){
		cin>>number;
	}
 
	int answer = 0;
 
	unordered_map<int,int> prefixSum;
 
	prefixSum[0] = 1;
 
	int sum = 0;
 
 
	for(int i=0; i<n; i++){
		sum += numbers[i];
 
 
		if(prefixSum.find((sum%k - i%k - 1 + k)%k) != prefixSum.end()){
			answer+=prefixSum[(sum%k-i%k-1+k)%k];
		}
 
		prefixSum[(sum%k-i%k-1+k)%k]++;
	}
 
	cout << answer;
 
	return 0;
}

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NSA0IAoxIDQgMyAyIDQ=

5 4 
1 4 3 2 4