Inflation Solution:

#include <bits/stdc++.h>

using namespace std;

int main(){
    // #ifndef TESTING
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    // #endif

    int n_balloons;
    cin >> n_balloons;
    int balloons[n_balloons];
    for(int i = 0; i < n_balloons; i++){
        cin >> balloons[i];
    }
    sort(balloons, balloons + n_balloons);
    double smallest = 1;
    for(int i = 1; i <= n_balloons; i++){
        if(balloons[i - 1] > i){
            cout << "impossible" << endl;
            return 0;
        }
        double fraction = balloons[i - 1] / (double) i;
        if(fraction < smallest){
            smallest = fraction;
        }
    }
    cout << fixed << setprecision(7);
    cout << smallest << endl;

    return 0;
}