n = int(input())
k = list()
for i in range(n):
    a,b,c = map(int,input().split())
    k.append(a)
    k.append(b)
    k.append(c)

cnt = 0
num = 0
for i in range(1,11):
    cnt += int(k.count(i) / 2)
    num += int(k.count(i) % 2)
print(cnt + int(num/4))