n = int(input())

S = [input() for _ in range(n)]

d = {}
ans = 0
for i in range(n):
	for j in range(n):
		if i == j:
			continue
		s = S[i] + S[j]
		if s in d:
			continue
		d[s] = 1
		ans +=1 

print(ans)