#include <iostream>
#include <math.h>

using namespace std;

double t[10000]={};
int idx=0;

double step(double x, double y){
    if(floor(x/2)!=x/2){
        t[idx]=y;
        idx++;
    }
    if(x==1){
        double temp=0;
        for(int i=0;i<=idx;i++)
            temp=temp+t[i];
        return temp;
    }else{
        x=floor(x/2);
        y=y*2;
        return(step(x,y));
    }
    return 0;
}

int main(){
    while(true){
        cout<<"enter 2 numbers separated with space"<<endl;
        double in1=0;
        double in2=0;
        cin>>in1>>in2;
        cout<<step(in1,in2)<<endl;
        for(int i=0;i<10000;i++)
            t[i]=0;
        idx=0;
    }
    return 0;
}