n = int(input())
lst = []
for i in range(0..n):
	lst[i] = input()
dic = {}
for i in range(0..n):
	for j in range(0..n):
		if i == j:
			continue
		s = lst[i] + lst[j]
		if s in dic:
			continue
		dic[s] = s
print(count(dic))