A frog climbs \(u\) metres each day and slips \(d\) metres after every day except the day it reaches the top. Find when it first reaches height \(h\).

Input

One line contains integers \(h,u,d\), with \(u>d\).

The input satisfies:

• \(1 <= h,u,d <= 10^9\)
• \(u>d\)

Output

Print the number of days.

Example

Input

2 6 5

Output

1