n = int(input())
item = [0] * 14
for i in range(n):
    a, b, c = [ int(v) for v in input().split() ]
    item[a] += 1
    item[b] += 1
    item[c] += 1
total += sum([i // 2 for i in item])
total += sum([i % 2 for i in item]) // 4
print(total)