P14875 [AtCoder] Takahashi has many red balls and blue balls. Now, he will place them in a row.
普及-
题目描述

Takahashi has many red balls and blue balls. Now, he will place them in a row.
Initially, there is no ball placed.
Takahashi, who is very patient, will do the following operation 10^{100} times:
- Place A blue balls at the end of the row of balls already placed. Then, place B red balls at the end of the row.
How many blue balls will be there among the first N balls in the row of balls made this way?

-----Constraints-----
- $1 \leq N \leq 10^{18}$
- $A, B \geq 0$
- $0 < A + B \leq 10^{18}$
- All values in input are integers.

-----Input-----
Input is given from Standard Input in the following format:
N A B

-----Output-----
Print the number of blue balls that will be there among the first N balls in the row of balls.

-----Sample Input-----
8 3 4

-----Sample Output-----
4

Let b denote a blue ball, and r denote a red ball. The first eight balls in the row will be bbbrrrrb, among which there are four blue balls.

输入格式

见题面

输出格式

见题面

样例输入
8 3 4
样例输出
4