#include<iostream>
#include<cstdio>
#include<cctype>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;
const int maxn=10003;
int n,k,a[maxn],l=0,r=0,mid;
inline void in(int &x){
    x=0;int f=1;char t=getchar();
    while(!isdigit(t)){if(t=='-')f=-1;t=getchar();}
    while(isdigit(t)){x=x*10+t-48;t=getchar();}
    x*=f;
}
inline void work(){
	in(n);in(k);
	double di;
	for(int i=1;i<=n;i++){
		scanf("%lf",&di);
		a[i]=(float)di*100.0;
		r=max(r,a[i]);
	}
	r++;
	while(l+1<r){
		mid=(l+r)/2;
		int cnt=0;
		for(int i=1;i<=n;i++){
		cnt+=a[i]/mid;
		}
		if(cnt>=k) l=mid;
		else r=mid;
	}
	printf("%.2lf",l/100.0);
}
inline int mian(){
	freopen("cable.in","r",stdin);
	freopen("cable.out","w",stdout);
	work();
}
int miku=mian();
int main(){;}