#include <stdio.h>

#include <math.h>

int main()

{

int m=0,n=0,p=0,sum=0,result=0;

scanf("%d",&n);

scanf("%d",&m);

for(p=0;p<=m;p++)

{

sum = n * pow(2,p);

result = result+sum;

}

printf("%d\n",result);

return 0;

}