N=int(input())
data=[[int(s) for s in input().split()] for i in range(N)]
D=[]
ans=0
for i in range(N):
    for j in range(3):
        D.append(data[i][j])
x=len(D)
for i in range(1,11):
    ans+=D.count(i)//2
    x-=(D.count(i)//2)*2
ans+=x//4
print(ans)