#include <bits/stdc++.h>
using namespace std;

void executeTime() {
    cerr << "Time Taken: " << (float)clock() / CLOCKS_PER_SEC << " secs";
}

int main() {


    int n, k; cin >> n >> k;

    vector<int> v(n);
    for (auto &x : v) {
        cin >> x;
    }


    unordered_map<int, int> mp;

    int p = 0, ans = 0;
    for (int i = 0; i < n; i++) {
        p += v[i];

        p %= k;

        ans += mp[p - i - 1];

        mp[p - i]++;
    }

    cout << ans << endl;



    executeTime();
    return 0;
}