import java.util.*;
 
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        long k = sc.nextLong();
 
        long[] arr = new long[n + 1];
        long[] prefix = new long[n + 1];
 
        for (int i = 1; i <= n; i++) {
            arr[i] = sc.nextLong();
            prefix[i] = prefix[i - 1] + arr[i];
        }
 
        Map<Long, Long> freq = new HashMap<>();
        freq.put(0L, 1L);
 
        int count = 0;
        for (int j = 1; j <= n; j++) {
            long key = (prefix[j] - j) % k;
            if (key < 0) key += k;
 
            count += freq.getOrDefault(key, 0L);
            freq.put(key, freq.getOrDefault(key, 0L) + 1);
        }
 
        System.out.println(count);
        sc.close();
    }
}
 

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