完整版

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