file = open("8A.txt")
A = list(map(int, file.readlines()))
count = 0
for i in range(len(A)):
    for j in range(i + 1, len(A)):
        if (A[i] + A[j]) % 80 == 0 and (A[i] > 50000 or A[j] > 50000):
            count += 1
print(count)