#Медленный способ
file = open('1A.txt')
A = list(map(int, file.readlines()))
n = A[0]
A = A[1:]
count = 0
for i in range(n):
    for j in range(i + 1, n):
        if (A[i] + A[j]) % 2 == 0:
            count += 1
print(count)

#Статический способ
file = open('1B.txt')
A = list(map(int, file.readlines()))
n = A[0]
A = A[1:]
k0 = 0
k1 = 0
for i in range(n):
    if A[i] % 2 == 0:
        k0 += 1
    else:
        k1 += 1
print(k0 * (k0 - 1) // 2 + k1 * (k1 - 1) // 2)

#Динамический способ
file = open('1B.txt')
A = list(map(int, file.readlines()))
n = A[0]
A = A[1:]
k = [0] * 2
count = 0
for i in range(n):
    ost = (2 - A[i] % 2) % 2
    count += k[ost]
    k[A[i]%2] += 1
print(count)