import sys
input=lambda: sys.stdin.readline().rstrip()
n=int(input())
C=[0]*10
for _ in range(n):
  a,b,c=map(int,input().split())
  C[a-1]+=1
  C[b-1]+=1
  C[c-1]+=1
ans=0
rem=0
for i in range(10):
  ans+=C[i]//2
  rem+=C[i]%2
print(ans+rem//4)