#include<stdio.h>
int main()
{
float x;
int n,i;
double t,z;
z=1.0;
scanf("%f%d",&x,&n);
t=x;
for(i=2;i<=n;i++)
{
z=z+(double)t;
t*=x;
}
z=z+(double)t;
printf("%.2f",z);
}