Задача: дачники (работает)

n = int(input())
count = 0
def line(x,y,x1,y1,x2,y2,x3,y3):
    if x1 == x2:
        if x1 >= x3 and x1 >= x: return True
        elif x1 <= x3 and x1 <= x: return True
        else: return False
    elif y1 == y2:
        if y1 >= y3 and  y1 >= y: return True
        elif y1 <= y3 and y1 <= y: return True
        else: return False
    else:
        x0 = x1-x2
        y0 = y1-y2
        k = y0/x0
        b = y1-x1*k
        if y3 >= k*x3+b and y >= k*x+b: return True
        elif y3 <= k*x3+b and y <= k*x+b: return True
        else: return False

for i in range(n):
    (x,y,x1,y1,x2,y2,x3,y3,x4,y4) = map(int,input().split())
    if line(x,y,x1,y1,x2,y2,x3,y3) and line(x,y,x2,y2,x3,y3,x4,y4) and line(x,y,x3,y3,x4,y4,x1,y1) and line(x,y,x4,y4,x1,y1,x2,y2):
        count+=1
print(count)