Veshy is taking a class in linear algebra! He comes across a problem about the rotations of points with respect to the origin. However, he deems this too trivial so he comes up with the following problem instead:

Veshy chooses two points located at integer coordinates, ~A~ and ~B~, on the 2D plane. There is initially a token at ~A~. Veshy also has a sequence of ~N~ points, all located at integer coordinates, on this plane, ~a_1, a_2, \dots, a_N~. One operation is defined as choosing some index ~i~ and rotating the token by an arbitrary angle around ~a_i~. However, if Veshy previously performed an operation on index ~i~, he is only allowed to perform an operation on index ~j~ if ~j>i~. Determine if it's possible to move the token from ~A~ to ~B~, and if so, the minimum number of operations required.

Constraints

In all subtasks,
~1 \le N \le 500~
The absolute value of all coordinates will be less than or equal to ~10^9~.

Subtask 1 [5%]

~N = 1~

Subtask 2 [10%]

~1 \le N \le 2~

Subtask 3 [25%]

~1 \le N \le 15~

Subtask 4 [60%]

No additional constraints.

Input Specification

The first line contains one integer, ~N~.
The second line contains two space-separated integers, ~A_x~ and ~A_y~, the coordinates of point ~A~.
The third line contains two space-separated integers, ~B_x~ and ~B_y~, the coordinates of point ~B~.
The next ~N~ lines contain two space-separated integers, ~x_i~ and ~y_i~ the coordinates of point ~a_i~.

Output Specification

Output one line containing one integer, the minimum number of operations if it's possible and -1 otherwise.

Sample Input

3
0 0
4 0
1 0
2 3
3 0

Sample Output

1

Explanation for Sample Output

One sequence of operations would be to rotate the token ~180^\circ~ around ~a_1~ and then another ~180^\circ~ around ~a_3~. This sequence is shown in green. This would require two operations.
Another sequence would be rotating the token ~67.38^\circ~ counter-clockwise around ~a_2~. This sequence is shown in blue. This would require one operation and it can be shown that there is no shorter sequence.