import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int m = sc.nextInt(), t = sc.nextInt(), s = sc.nextInt();
        if( (s/t)*t < s ) m = m-s/t-1;
        else m = m-s/t;
        if(m<0)System.out.print(0);
        else System.out.print(m);
    }
}