#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstdio>
#define bbn long long
using namespace std;
int n,k,l,r=100000000,ans;
int a[10000001];
int main(){
    cin>>n>>k;
    for(int i=1;i<=n;i++)
    {    
		double p;
		cin>>p;
		a[i]=p*100;
	}
    while(l<=r)
    {
        int mid=l+r>>1;
        if(mid==0)
			break;
		else
        {
			int sum=0;
    		for(int i=1;i<=n;i++)
				sum+=a[i]/mid;
			if(sum>=k)
            {
        		l=mid+1;
				ans=mid;
			}
        	else 
				r=mid-1;
		}
        
    }
    printf("%lf",ans/100);
    return 0;
}