import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		Long[] L=new Long[n];
		for(int i=0;i<n;i++){
			L[i]=sc.nextLong();
		}
		long k=sc.nextLong();
		double sup=Integer.MAX_VALUE;//不可能な長さ
		double low=0;//可能な長さ
		for(int i=0;i<300;i++){
			long count=0;
			double mid=(sup+low)/2;
			for(int j=0;j<n;j++){
				count+=(long)(int)(L[j]/mid);
			}
			if(count>=k){
				low=mid;
			}else{
				sup=mid;
			}
			
		}
		System.out.println(low);
	}
}