from collections import defaultdict

def getlist():
	return list(map(int, input().split()))

D = defaultdict(int)
N = int(input())
for i in range(N):
	a, b, c = getlist()
	D[a] += 1
	D[b] += 1
	D[c] += 1

c = 0
ans = 0
for i in D:
	if D[i] % 2 == 0:
		ans += int(D[i] // 2)
	else:
		ans += int(D[i] // 2)
		c += 1

ans += int(c // 4)
print(ans)