N=int(raw_input())
cnt = [0 for i in range(11)]
for i in range(N):
   a,b,c=map(int,raw_input().split())
   cnt[a]+=1
   cnt[b]+=1
   cnt[c]+=1
ans=0
r=0
for i in range(11):
   ans += cnt[i]/2
   if cnt[i]%2!=0:
      r+=1
print ans+r/4