993 992 991
 100 1 10
 960 935 994
 99 8 99
 60 16 1
 759 10 258
 24 19 9
 196 169 144
 1000 999 1
 945 812 917
 1000 100 10
 500 300 300
 888 777 1000
 2 1 4
 24 12 12
 767 2 514
 2 1 2
 1000 1 1
 5 2 1
 70 32 1
 765 123 899
 17 7 10
 5 4 10
 888 777 888
 66 38 4
 1000 999 1000
 9 3 300
 244 87 4
 765 123 45
 1000 1 1000
 305 203 421
 100 10 1
 64 12 8
 894 1 999
 2 1 1
 18 14 10
 6 2 4
 888 777 1
 27 26 1
 2 1 3
 5 1 5
 7 3 200
 561 31 917
 17 10 7
 93 74 831

1
 990
 27
 1127
 3
 19325
 3
 24
 1
 151
 90
 200
 143
 4
 12
 196605
 2
 999
 2
 2
 4693
 15
 3
 127
 3
 2
 600
 8
 235
 999000
 212
 9
 35
 892107
 1
 3
 8
 1
 1
 3
 20
 267
 15678
 5
 214

import java.util.Scanner;


public class A 
{

	static int dataNeededToWatchOneSecond;
	static int dataDownloadedPerSecond;
	static int secondsInVideo;
	static int minimumValue = 0;
	static int maximumValue;
	final public static void main(String[] args)
	{
		Scanner s = new Scanner(System.in);
		dataNeededToWatchOneSecond = s.nextInt();
		dataDownloadedPerSecond = s.nextInt();
		secondsInVideo = s.nextInt();
		maximumValue = secondsInVideo * dataNeededToWatchOneSecond / dataDownloadedPerSecond;
		int low = minimumValue;
		int high = maximumValue;
		int current = (high + low)/2;
		while (low < current)
		{
			if (testCase(current) == false)
			{
				low = current;
				//System.out.println("Low = " + low);
			} else
			{
				high = current;
				//System.out.println("High = " + high);
			}
			current = (high + low)/2;
		}
		int print = high;
		if (testCase(current) == true)
		{
			print = current;
		}
		if (testCase(low) == true)
		{
			print = low;
		}
		System.out.println(print);
	}
	
	//return true if waiting testValue seconds is big enough
	//return false if that does not
	final public static boolean testCase(int testValue)
	{
		int startingData = dataDownloadedPerSecond * testValue;
		int dataAmount = startingData;
		for (int seconds = 1; seconds <= secondsInVideo; seconds++)
		{
			dataAmount -= dataNeededToWatchOneSecond;
			dataAmount += dataDownloadedPerSecond;
			if (dataAmount < 0)
			{
				return false;
			}
		}
		return true;
	}
}
	  		 	   	  		 		      	