N = int(input())

item = [0 for i in range(10)]

for i in range(N):
    drop = input().split()
    item[int(drop[0])-1] += 1
    item[int(drop[1])-1] += 1
    item[int(drop[2])-1] += 1


def solve(item):
    Lvcount = 0
    remaining = 0
    for k in range(len(item)):
        Lvcount += item[k] // 2
        remaining += item[k] % 2
    Lvcount += remaining // 4
    return Lvcount
solve

Lv = solve(item)
print(Lv)