Background

Special for beginners, ^_^

Description

Format

Input

Output

Samples

2
7 1
-1 -4
-3 1
-3 -1
2 3
2 4
2 -2
6 -2
4 0
0 4
-12 18
0 27
-34 51

4
2

Limitation

1s, 1024KiB for each test case.