C acm10071 Back to High School Physics

#include <stdio.h>
#include <stdlib.h>

int v,t,s;

int main()
{
     while(scanf("%d %d",&v,&t)==2)
     {
        s =2*v*t;
        printf("%d\n",s);              
     }  
   
 system("pause");
 //return 0;   
}