n=int(input())

item=[0]*10
ans=0
for i in range(n):
    a,b,c=map(int,input().split())
    item[a-1]+=1
    item[b-1]+=1
    item[c-1]+=1

for i in item:
    if i>=2:
        ans+=(i//2)
        
ans+=(sum(x==1 for x in item)//4)      
print(ans)