又是openjudge runtime error ，java新手求解

[qq_36321599]

package sdmda.bupt.edu.cn;
import java.util.Scanner;
public class Main {

public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int n=scanner.nextInt();
int x=scanner.nextInt();
int y=scanner.nextInt();
scanner.close();
if(y>n*x||x<=0||y<0)
{
return ;
}
else
{
int z=(int)(n-Math.ceil((double)y/x));
System.out.println(z);
}
}

}