N = int(input())
items=[0]*10
for i in range(N):
    a,b,c = map(int,input().split())
    a-=1
    b-=1
    c-=1
    items[a]+=1
    items[b]+=1
    items[c]+=1

ans=0
cnt=0
for i in range(10):
    ans+=items[i]//2
    cnt+=items[i]%2

print(ans+cnt//4)