n = int(input())
a = [0] * 10
for i in range(n):
    b,c,d = map(int,input().split())
    a[b-1] += 1
    a[c-1] += 1
    a[d-1] += 1
ans = 0
for i in range(10):
    ans += a[i] // 2
    a[i] %= 2
ans += sum(a) // 4
print(ans)