n, p = map(int, input().split())
a = list(map(int, input().split()))
a.sort()
max_diff = a[-1] - a[0]
ans = 0

current_power = p

while current_power <= max_diff:
    from collections import defaultdict
    mod_count = defaultdict(int)
    for num in a:
        mod = num % current_power
        mod_count[mod] += 1
    c_k = 0
    for cnt in mod_count.values():
        c_k += cnt * (cnt - 1) // 2
    ans += c_k
    next_power = current_power * p
    if next_power > max_diff:
        break
    current_power = next_power

print(ans)