#include <stdio.h>
int main(){
	int count1=0,count2=0;
	float sum1=0.0,sum2=0.0;
	int chushu,n;
	scanf("%d",&n);
	scanf("%d",&chushu);
	for(int i=1;i<=n;i++){
		if(i%chushu==0){
			sum2+=i;
			count2++;
		}
		else{
			sum1+=i;
			count1++;
		}
	}
	printf("%.1f %.1f",sum2/count2,sum1/count1);
	return 0;
}

求助