n = int(input())
C = [0]*10
for i in range(n):
    a,b,c = map(int, input().split())
    a,b,c = a-1, b-1, c-1
    C[a] += 1
    C[b] += 1
    C[c] += 1
ans = 0
s = 0
for c in C:
    q, r = divmod(c, 2)
    ans += q
    s += r
ans += s//4
print(ans)