Robot Instructions
문제
Bessie is learning how to control a robot she has recently received as a gift.
The robot begins at point on the coordinate plane and Bessie wants the robot to end at point . Bessie initially has a list of () instructions to give to the robot, the -th of which will move the robot units right and units up (or left or down when and are negative, respectively).
For each from to , help Bessie count the number of ways she can select instructions from the original such that after the instructions are executed, the robot will end at point .
입력
The first line contains . The next line contains and , each in the range . The final lines describe the instructions. Each line has two integers and , also in the range .
It is guaranteed that and for all .
출력
Print lines, the number of ways Bessie can select instructions from the original for each from to .
힌트
In this example, there are six ways Bessie can select the instructions:
(-2,0) (3,0) (4,0) (0,10) (0,-10) (0,10) (1 2 3 5 6 7) (-2,0) (3,0) (4,0) (0,10) (1 2 3 5) (-2,0) (3,0) (4,0) (0,10) (1 2 3 7) (5,0) (0,10) (0,-10) (0,10) (4 5 6 7) (5,0) (0,10) (4 5) (5,0) (0,10) (4 7)
For the first way, the robot's path looks as follows:
(0,0) -> (-2,0) -> (1,0) -> (5,0) -> (5,10) -> (5,0) -> (5,10)
예제
예제 1
7 5 10 -2 0 3 0 4 0 5 0 0 10 0 -10 0 10
0 2 0 3 0 1 0