n=int(input())
a=[]
for i in range(n):
    b,c,d=map(int,input().split())
    a.append(b)
    a.append(c)
    a.append(d)
from collections import Counter
c=Counter(a)
amr=0
pw=0
for i in c.values():
    pw+=i//2
    amr+=i%2
print(pw+amr//4)