python3 前缀和
N, K = map(int, input().split())
s = [0]
cnt = [0 for i in range(K)]
for i in range(1, N+1):
a = int(input())
s.append(a)
s[i] += s[i-1]
res = 0
cnt[0] = 1
for r in range(1, N+1):
res += cnt[s[r] % K]
cnt[s[r] % K] += 1
print(res)