n = int(input())
s = [0 for _ in range(10)] #s=[0,0,0,0,...,0](len=10)
count = 0
for i in range(n):
	a=list(map(int,input().split()))
	for j in range(3):
		s[a[j]-1] += 1
s = sorted(s)[::-1]
for i in range(10):
	if s[i]>=2:
		count += s[i]//2
		s[i] = s[i]%2
s = sorted(s)[::-1]
if s[7]==1:
	count += 2
elif s[3]==1:
	count += 1
print(count)