N=int(input())
I=[0 for _ in range(10+1)]
for _ in range(N):
    a,b,c=map(int,input().split())
    I[a]+=1
    I[b]+=1
    I[c]+=1
ans=0
for i in range(11):
    ans+=I[i]//2
    I[i]%=2
ans+=sum(I)//4
print(ans)