N = int(input())
ABCs = [list(map(int, input().split())) for i in range(N)]
cnt = [0 for i in range(10)]
for a in ABCs:
    cnt[a[0]-1] += 1
    cnt[a[1]-1] += 1
    cnt[a[2]-1] += 1

sum = 0
res = 0
for c in cnt:
    sum += c // 2
    res += c % 2
sum += res // 4
print(sum)