# your code goes here
n = int(input())
A = list(map(int, input().split()))
d = int(input())
counter = 0
mp = {}
for k in range(n):
    real = A[k] % d
    r = d - real
    r = r % d
    counter += mp.get(r, 0)
    for u in range(k):
        sum_val = A[u] + A[k]
        sum_val = sum_val % d
        mp[sum_val] = mp.get(sum_val, 0) + 1
print(counter)