#21173

#21173
f = open('4.txt')
n = int(f.readline())
#print(n)
# print(len(f.readlines()))
a = []

for i in range(n):
    q = int(f.readline())
    a.append(q)
#print(a)
c = 0
for i in range(n):
    for j in range(i + 1, n):
        if ((a[i] + a[j]) % 2 == 0) and ((a[i] * a[j]) % 2 == 1):
            c += 1

print(c)