UVa Problem ID 10071 (Back To High School Physics)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws IOException 
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuffer sb=new StringBuffer("");
        String input;
        while ((input=br.readLine())!=null) {
			String s[]=input.split(" ");
			int v=Integer.parseInt(s[0]);
			int t=Integer.parseInt(s[1]);
			if(v<-100 || v>100 || t<0 || t>200)
				break;
			sb.append((2*v*t));
			sb.append("\n");
        }
        System.out.print(sb);
    }
}