import sys
from collections import defaultdict

try:
    import mydebug

    def dprint(*objects):
        print(*objects)
except:
    def dprint(*objects, sep='', end='\n'): pass

n = int(input())
dic = defaultdict(int)
a = [0, 0, 0]
for i in range(n):
    a[0], a[1], a[2] = [int(x) for x in input().split()]
    for j in range(3):
        dic[a[j]] += 1

ans = 0
left = 0
for k, v in dic.items():
    ans += v // 2
    left += v % 2
ans += left // 4

print(ans)