Ostoz

To treat kidney fibrocystic osteosis, you must cross a swamp using planks that connect tussocks. Once a tussock is stepped on, it sinks.

Your goal is to cure the maximum number of people suffering from kidney fibrocystic osteosis.

Input

The first line of the input provides the number of planks, n (1 ≤ n ≤ 1000). For each plank, the coordinates of the tussocks at both ends of the plank are given (-2^31 ≤ x_i, y_i ≤ 2^31). Following this, the coordinates of the starting and ending points are provided (these points are distinct, and no plank connects them directly). All numbers in the input are integers.

Output

Output the maximum number of people that can be cured.

Examples