#include<stdio.h>
#include<math.h>  
int main()  
{  
    double n;
    int m;  
    while(~scanf("%lf%d",&n,&m))  
    {  
        double y=n;  
        m=m-1;  
        while(m--)  
        {  
            n=sqrt(n);  
            y=y+n;  
        }  
        printf("%.2lf\n",y);  
    }  
    return 0;  
}