N = int(input())
counter = [0]*(11)
for i in range(N):
    a,b,c = map(int,input().split())
    counter[a] += 1
    counter[b] += 1
    counter[c] += 1
lv = 0
rm = 0
for i in range(1,11):
    lv += counter[i]//2
    rm += counter[i]%2
lv += rm//4
print(lv)