bag = [0] * 10
ans = 0
for i in range(int(input())):
    itm = list(map(int, input().split()))
    for j in range(3):
        bag[itm[j] - 1] += 1
for i in range(10):
    if(bag[i] // 2 > 0):
        ans += bag[i] // 2
        bag[i] -= bag[i] // 2 * 2
print(ans + sum(bag) // 4)