63pts!995!!!

#include<iostream>
#include<cmath>
#include<cstring>
using namespace std;
double a[10000],n,k,sum=0,l=0,r=0;
int judge(double x){
    int ans=0;
    for(int i=1;i<=n;i++) ans+=a[i]/x;
    return ans>=m;
}
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++) cin>>a[i],r+=a[i];
    while(r-l>0.0001){
        double mid=(l+r)/2;
        if(judge(mid)) l=mid;
        else r=mid;
    }
    printf("%.2lf",l-1);
    return 0;
}