main()
{
int i,j,x,n;
float t,fz,fm,s=0;
scanf("%d%d",&x,&n);
for(i=0;i<n;i++)
{fz=fm=1.0;
for(j=1;j<=i;j++)
{fz*=x;
fm*=j;
t=fz/fm;
}
s+=t;
printf("%f",s);