import bisect
import sys
n = int(input())
stars = []
for i in range(n):
    x, y, z = map(int, input().split())
    stars.append((x, y, z))
stars.sort(key = lambda P: (P[0], P[1]))
coor = []
ans = 0
for x,y,z in stars:
    if z == 0:
        bisect.insort(coor, y)
    else:
        pos = bisect.bisect_left(coor, y)
        if pos>0:
            ans += 1
            coor.pop(pos-1)
print(ans)