题干：

Valeric and Valerko missed the last Euro football game, so they decided to watch the game's key moments on the Net. They want to start watching as soon as possible but the connection speed is too low. If they turn on the video right now, it will "hang up" as the size of data to watch per second will be more than the size of downloaded data per second.

The guys want to watch the whole video without any pauses, so they have to wait some integer number of seconds for a part of the video to download. After this number of seconds passes, they can start watching. Waiting for the whole video to download isn't necessary as the video can download after the guys started to watch.

Let's suppose that video's length is c seconds and Valeric and Valerko wait tseconds before the watching. Then for any moment of time t0, t ≤ t0 ≤ c + t, the following condition must fulfill: the size of data received in t0 seconds is not less than the size of data needed to watch t0 - t seconds of the video.

Of course, the guys want to wait as little as possible, so your task is to find the minimum integer number of seconds to wait before turning the video on. The guys must watch the video without pauses.

Input

The first line contains three space-separated integers a, b and c (1 ≤ a, b, c ≤ 1000, a > b). The first number (a) denotes the size of data needed to watch one second of the video. The second number (b) denotes the size of data Valeric and Valerko can download from the Net per second. The third number (c) denotes the video's length in seconds.

Output

Print a single number — the minimum integer number of seconds that Valeric and Valerko must wait to watch football without pauses.

Examples

Input

4 1 1

Output

3

Input

10 3 2

Output

5

Input

13 12 1

Output

1

Note

In the first sample video's length is 1 second and it is necessary 4 units of data for watching 1 second of video, so guys should download 4 · 1 = 4 units of data to watch the whole video. The most optimal way is to wait 3 seconds till 3 units of data will be downloaded and then start watching. While guys will be watching video 1 second, one unit of data will be downloaded and Valerik and Valerko will have 4 units of data by the end of watching. Also every moment till the end of video guys will have more data then necessary for watching.

In the second sample guys need 2 · 10 = 20 units of data, so they have to wait 5 seconds and after that they will have 20 units before the second second ends. However, if guys wait 4 seconds, they will be able to watch first second of video without pauses, but they will download 18 units of data by the end of second second and it is less then necessary.

 

题目大意：

   输入a,b,c，第一个数字(a)表示观看一秒钟视频所需的数据大小。第二个数字(b)表示每秒可以从网络下载的数据大小。第三个数字(c)表示视频的长度(以秒为单位)。问我如果想中间不停顿的播放，则至少需要等他下载多少秒再开始播放？

解题报告：

    菜啊，，想错式子了啊刚开始。一直想推一个追及的式子，结果用时间的等式或者用下载量的等式，最后都推出来类似1=1的东西，，，崩溃，，后来发现不能这么看，因为提前几秒下载的时间你是不知道的啊。其实设提前下载t秒，一共视频是c秒，这个告诉你了，所以t*b+c*b=a*c就可以了。。。。并且需要向上取整。。。水题

AC代码：

#include<bits/stdc++.h>
using namespace std;int main()
{int a,b,c;double x;cin>>a>>b>>c;x=a*c-b*c;printf("%d\n",(int)ceil(x/b));return 0 ;
}