#include #define rep(i, a) for (int i = 0; i < (a); i++) #define rep2(i, a, b) for (int i = (a); i < (b); i++) #define repr(i, a) for (int i = (a) - 1; i >= 0; i--) #define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--) using namespace std; typedef long long ll; const ll inf = 1e9; const ll mod = 573; ll N, K, L[200000]; int main() { cin >> N; rep (i, N) cin >> L[i]; cin >> K; double l = 1e-8; double r = 1e9 + 10; rep (ii, 200) { ll num = 0; double m = (l + r) / 2; rep (i, N) { num += floor(L[i] / m); if (num >= 1e10) { break; } } if (num >= K) { l = m; } else { r = m; } } printf("%.20f\n", l); return 0; }