N=int(raw_input())
d={}
for _ in xrange(N):
  a,b,c=map(int,raw_input().split())
  if a not in d: d[a]=0
  if b not in d: d[b]=0
  if c not in d: d[c]=0
  d[a]+=1
  d[b]+=1
  d[c]+=1
x=0
for k,v in d.items():
  x+=v/2
  if v%2==0: del d[k]
  else: d[k]=1
x+=len(d)/4
print x