n=int(input())
L=[0]*11
for _ 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]=L[i]%2
ans+=sum(L)//4
print(ans)