n=int(input())
l=[list(map(int,input().split())) for i in range(n)]
ct=[0]*10
for i in range(n):
  for j in range(3):
    ct[l[i][j]-1]+=1
s=sum(ct)
ans=0
for i in range(10):
  x=ct[i]//2
  ans+=x
  s-=x*2
print(ans+s//4)