1779Climbing Worm

1779   Climbing Worm

题目描述

An inch worm is at the bottom of a well n inches deep. It has enough energy to climb u inches every minute, but then has to rest a minute before climbing again. During the rest, it slips down d inches. The process of climbing and resting then repeats. How long before the worm climbs out of the well? We'll always count a portion of a minute as a whole minute and if the worm just reaches the top of the well at the end of its climbing, we'll assume the worm makes it out.

输入格式:

There will be multiple problem instances. Each line will contain 3 positive integers n, u and d. These give the values mentioned in the paragraph above. Furthermore, you may assume d < u and n < 100. A value of n = 0 indicates end of output.


输出格式:

Each input instance should generate a single integer on a line, indicating the number of minutes it takes for the worm to climb out of the well.

输入样例 复制
10 2 1
20 3 1
0 0 0
输出样例 复制
17
19

说明

3
4
通过提交
时空限制2000ms/64mb
题目来源
评测方式在线评测
题目类型
难        度