N = int(input())
ABC = [list(map(int, input().split())) for _ in range(N)]
D = [0 for _ in range(11)]
for a, b, c in ABC:
    D[a]+=1
    D[b]+=1
    D[c]+=1
cnt = 0
for i in range(1, 11):
    cnt+=D[i]//2
    D[i]%=2
S = sum(D)
cnt+=S//4
print(cnt)