#include <bits/stdc++.h>
#define INIT std::ios::sync_with_stdio(false);std::cin.tie(0);
#define VAR(type, a) type a;std::cin>>a;
// VAR(int, x);
#define OUT(d) std::cout<<(d);
#define FOUT(d, n) std::cout<<std::fixed<<std::setprecision(n)<<(d);
#define SP std::cout<<" ";
#define ENDL std::cout<<"\n";
#define VEC(type, c, n) std::vector<type> c(n);for(auto& i:c)std::cin>>i;
#define MAT(type, c, m, n) std::vector<std::vector<type>> c(m, std::vector<type>(n));for(auto& r:c)for(auto& i:r)std::cin>>i;
#define ALL(a) (a).begin(),(a).end()
#define FOR(i,a,b) for (int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);--i)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)

using ll = long long;

signed main(){
    INIT;
    VAR(ll, n);
    VEC(ll, l, n);
    VAR(ll, k);
    double left = 0, right = 1000000000;
    double mid;
    REP(i, 1000){
        mid = (left+right)/2;
        ll cnt = 0;
        REP(j, n){
            cnt += std::floor(l[j]/mid);
        }
        if(k<=cnt) left  = mid;
        else       right = mid;
    }
    FOUT(mid, 10)ENDL;
    return 0;
}