#include<bits/stdc++.h>
using namespace std;
int main()
{
	double a;
	int n,k;
	cin >> n >> k;
	for (int i = k ; i <= n ; i += k){
		a += i;
	}
	printf("%.if",a / (n / k));
	a = (1 + n) * n / 2 - a;
	printf("%.1f",a / (n - (n / k)));
	return 0;
}