from collections import defaultdict

N = int(input())
abc = tuple(tuple(int(s) for s in input().split()) for i in range(N))

d = defaultdict(int)
for v in abc:
  for _ in v:
    d[_] += 1

p = 0
for k, v in d.items():
  if v >= 2:
    p += v // 2
  p += (v % 2) * 0.25

print(int(p))