Problem 26721 --递推--火车站

26721: 递推--火车站

Time Limit: 1 Sec  Memory Limit: 128 MB
Submit: 12  Solved: 6
[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

1 6 7 3

Sample Output

2

HINT

Source

[Submit][Status]