import sys
#sys.setrecursionlimit(n)
import heapq
import re
import bisect
import random
import math
import itertools
from collections import defaultdict, deque
from copy import deepcopy

n = int(input())
c = itertools.count(0, 1)
d = defaultdict(int)
count = 0
for i in c:
    if i >= n:
        break
    a, b, c = map(int, input().split())
    d[a] += 1
    d[b] += 1
    d[c] += 1
f = 0
for i in d:
    t = d[i] // 2
    d[i] -= t * 2
    count += t
    f += d[i]
print(count + (f // 4))