file = open('9A.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]) == 2000:
            count += 1
print(count)

file = open('9B.txt')
A = list(map(int, file.readlines()))
k = [0] * 2000
for i in range(len(A)):
    ost = A[i] % 2000
    if A[i] < 2000:
        k[ost] += 1
count = k[0] * (k[0] - 1) // 2 + k[1000] * (k[1000] - 1) // 2
for i in range(1, 1000):
    count += k[i] * k[2000 - i]
print(count)