Problem 26719 --递推--过河卒

26719: 递推--过河卒

Time Limit: 1 Sec  Memory Limit: 128 MB
Submit: 48  Solved: 12
[Submit][Status][Web Board][Creator:][下载FPS1元][添加到购物车][下载测试数据1元][52kb]

Description


Input

Output

Sample Input

4 8 2 4

Sample Output

0

HINT

Source

[Submit][Status]