#include <iostream>
#include<stdio.h>
#include<math.h>
using namespace std;
double h(double x,double n){
    if(n==1) return 1.0*sqrt(1+x);
    
    return 1.0*sqrt(n+h(x,n-1));
}
int main(){
    
    double x,n;
    cin>>x>>n;
    printf("%.2f",h(x,n));
    
}