N = int(input())
dat = [0] * 11
for _ in range(N):
    a,b,c = map(int,input().split())
    dat[a] += 1
    dat[b] += 1
    dat[c] += 1
ans = 0
for i in range(1,11):
    ans += dat[i] // 2
    dat[i] = dat[i] & 1
print(ans + sum(dat) // 4)