from collections import defaultdict
n = int(input())
cnt = 0
d = defaultdict(int)
for _ in range(n):
    a, b, c = map(int, input().split())
    d[a] += 1
    d[b] += 1
    d[c] += 1

for k, v in d.items():
    cnt += v // 2
    d[k] = v % 2

p = 0
for k, v in d.items():
    p += v
cnt += p // 4
print(cnt)