#include<iostream>
#include<cmath>
#define ll long long

using namespace std;

int main(){
    double w,d;
    cin >> w >> d;
    for(int i=0;i < d;i++){
        if(i != d-1) w -= floor(w/((d-i)*(d-i)));
    }
    cout << w << endl;
    return 0;
}