#include<bits/stdc++.h> using namespace std; int n,k; double cable[11451]; bool check(double x){ int cnt=0; for(int i=1;i<=n;i++) cnt+=(cable[i]/x); if(cnt>=k) return true; else return false; } int main(){ cin>>n>>k; double l=0,r=-1,ans=0; for(int i=1;i<=n;i++){ cin>>cable[i]; r=max(r,cable[i]); } int L=0,R=r*100; while(L<=R){ int mid=L+(R-L)/2; if(check((double)mid/100)){ ans=mid; L=mid+1; } else{ R=mid-1; } } ans/=100; if(ans<0.01){ cout<<0.00; } else{ cout<<fixed<<setprecision(2)<<ans<<endl; } }