N = int(input())
L = [0] * 11
for i in range(N):
	a, b, c = map(int, input().split())
	L[a] += 1
	L[b] += 1
	L[c] += 1
	
ans = 0
for i in range(11):
	ans += L[i] // 2
	L[i] %= 2
	
ans += sum(L) // 4
print(ans)