10071 - Back to High School Physics

A particle has initial velocity and constant acceleration. If its velocity after certain time is v then what will its displacement be in twice of that time?

 

Input

The input will contain two integers in each line. Each line makes one set of input. These two integers denote the value of v (-100 <= v <= 100) and t(0<=t<= 200) ( t means at the time the particle gains that velocity) 

 

Output

For each line of input print a single integer in one line denoting the displacement in double of that time.

 某一个粒子有一初速度和等加速度。假设在t 秒后此粒子的速度为v ，请问这个粒子在2t 秒后所经过的距离是多少。

Input

每组测试资料1列，有2个整数，分别代表v（-100 <= v <=100）和t（0 <= t <= 200）。

Output

对每组测试资料请输出这个粒子在2t 秒后所经过的距离是多少。

Sample Input

0 0
5 12

Sample Output

0
120

 解题思路：水题，直接套公式

#include<stdio.h>
int main()
{int v,t;
while(scanf("%d %d",&v,&t)!=EOF)
printf("%d\n",2*v*t);
return 0;
}