#include<bits/stdc++.h>
using namespace std;
inline void read(int &s){
    s=0;char c=getchar();
    while(c<'0'||c>'9')c=getchar();
    for(;c>='0'&&c<='9';c=getchar())s=(s<<1)+(s<<3)+(c^48);
}
int n,k;
int a[100005];
bool check(int x){
	int sum=0;
	for(int i=1;i<=n;i++){
		sum+=a[i]/x;
	}
	return sum>=k;
}

int main(){
	read(n),read(k);
	int l=0,r=1<<30,mid;
	for(int i=1;i<=n;i++){
     double t;
		scanf("%lf",&t);
		a[i]=(int)t*100;
	}
	while(l<=r){
		mid=(l+r)>>1;
		if(mid==0)break;
		if(check(mid)){
			l=mid+1;
		}else{
		    r=mid-1;
		}
	}
	printf("%.2f",r/100.0);
	return 0;
}