UVA_10071_Back_To_High_School

#include <iostream>
#include <cstdio>
#include <stdio.h>
#include <algorithm>
#include <cstring>
#include <cctype>
#include <sstream>
#include <stdlib.h>
#include <cmath>
#define LL unsigned long long
using namespace std;

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