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 x in range(10):
    if item[x]>=2:
        ans+=(item[x]//2)
        item[x]=item[x]%2
        
ans+=(sum(x==1 for x in item)//4)      
print(ans)