Poj Solution 2017

http://poj.org/problem?id=2017

import java.io.BufferedInputStream;   
import java.util.Scanner;   
  
/**  
 *poj2017  
 * @author NC  
 */  
public class Main {   
  
    public static void main(String[] args) {   
        Scanner scan = new Scanner(new BufferedInputStream(System.in)); 

  
        while (scan.hasNext()) {   
            int n = scan.nextInt();   
            if (n == -1) {   
                break;   
            }   
            int lastTime = 0;   
            int sum = 0;   
            for (int i = 0; i < n; i++) {   
                int speed = scan.nextInt();   
                int time = scan.nextInt();   
                sum = sum + speed * (time - lastTime);   
                lastTime = time;   
            }   
            System.out.println(sum + " miles");   
        }   
    }   
}