PKU Judge Online 2017 Speed Limit

■2017 Speed Limit

□Problem
省略．

□Solution
省略．

□Code

package p2017;

import java.util.*;
import java.lang.*;
import java.math.*;
import java.io.*;

import static java.lang.Math.*;
import static java.util.Arrays.*;

// AC
public class Main{

    Scanner sc=new Scanner(System.in);

    final int INF=Integer.MAX_VALUE;
    final double EPS=1e-9;

    void run(){
        for(;;){
            int n=sc.nextInt();
            if(n==-1)
                break;
            int ph=0;
            int tot=0;
            for(int i=0; i<n; i++){
                int v=sc.nextInt();
                int h=sc.nextInt();
                tot+=(h-ph)*v;
                ph=h;
            }
            println(tot+" miles");
        }
    }

    void print(String s){
        System.out.print(s);
    }

    void println(String s){
        System.out.println(s);
    }

    public static void main(String[] args){
        // System.setOut(new PrintStream(new BufferedOutputStream(System.out)));
        new Main().run();
    }
}