n=int(input())
lst=[0]*(11)
ans=0
for _ in range(n):
    a,b,c=map(int,input().split())
    lst[a]+=1
    lst[b]+=1
    lst[c]+=1
# print(lst)
for i in range(1,11):
    if lst[i]>=2:
        tmp=lst[i]//2
        ans+=tmp
        lst[i]-=(tmp*2)
tmp1=0
# print(lst,ans)
# print(lst)
for j in range(1,11):
    if lst[j]==1:
        tmp1+=1
        # print(tmp1)
# print(tmp1)
ans+=(tmp1//4)
print(ans)