N = int(raw_input())
a = [0]*N
b = [0]*10
up = 0
temp = 0

for  i in xrange(N):
	a[i] = map(int,raw_input().split())

for x in xrange(N):
	for i in xrange(3):
		b[a[x][i]-1] += 1

for x in xrange(10):
	temp = b[x]/2
	up += temp
	b[x] -= temp*2

up += sum(b)/4
print up