#include <bits/stdc++.h>
using namespace std;
 
int main() {
	// your code goes here
	int n, k; cin >> n >> k;
	vector<int> arr(n+1);
	vector<int> p(n+1);
	int psum = 0;
	for (int i = 1; i <= n; i++){
		cin >> arr[i];
		p[i] = p[i-1]+arr[i];
	}
 
	int count = 0;
	unordered_map<int, int> freq;
	freq[0] = 1;
	for(int j = 1; j <= n; j++){
		int rhs = ((p[j] % k) - (j % k) + k) % k;
		if(freq.find(rhs) != freq.end()){
			count += freq[rhs];
		}
 
		freq[rhs]++;
	}
 
	cout << count;
 
	return 0;
}

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NSA0CjEgNCAzIDIgNA==

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