item_kind = []
power_up = 0

for i in range(10):
    item_kind.append(0)

N = int(input())

for i in range(N):
    get_item = [int(x) for x in input().split()]
    for j in range(3):
        item_num = get_item[j]
        item_kind[item_num - 1] = item_kind[item_num - 1] + 1

for k in range(len(item_kind)):
    while item_kind[k] >= 2:
        item_kind[k] = item_kind[k] - 2
        power_up = power_up + 1
    
power_up = power_up + int(item_kind.count(1) / 4)

print(power_up)