N = int(input())
D = {}
for i in range(1,11) :
    D[str(i)] = 0
for i in range(N) :
    a,b,c = map(int,input().split())
    D[str(a)] += 1
    D[str(b)] += 1
    D[str(c)] += 1
ans = 0
for i in range(1,11) :
    ans += D[str(i)] // 2
    D[str(i)] %= 2
ans += sum(list(D.values())) // 4
print(ans)