//#include <bits/stdc++.h>

#include <iostream>
#include <algorithm>

#include <bitset>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <stack>
#include <queue>
#include <deque>
#include <cstring>
#include <string>
#include <utility>
#include <array>
#include <complex>
#include <valarray>

#include <cassert>
#include <cmath>
#include <functional>
#include <iomanip>
#include <chrono>
#include <random>
#include <numeric>


using namespace std;
//#define int long long

typedef long long ll;
typedef unsigned long long ull;
//typedef unsigned __int128 HASH;
typedef pair<int,int> pii;
typedef pair<ll, ll> pll;
typedef pair<ull, ull> pullull;
typedef pair<ll,int> plli;
typedef pair<double,int> pdi;
typedef pair<long double, int> pdbi;
typedef pair<int,pii> pipii;
typedef pair<ll,pll> plpll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<pii> vpii;
typedef vector<vector<int>> mat;

#define rep(i,n) for (int i=0;i<(n);i++)
#define rep2(i,a,b) for (int i=(a);i<(b);i++)
#define rrep(i,n) for (int i=(n);i>0;i--)
#define rrep2(i,a,b) for (int i=(a);i>b;i--)
#define pb push_back
#define fi first
#define se second
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()

const ll hmod1 = 999999937;
const ll hmod2 = 1000000000 + 9;
const int INF = 1<<30;
const ll INFLL = 1LL<<62;
const long double EPS = 1e-12;
const ll mod = 1000000000 + 7;
const int dx4[4] = {1, 0, -1, 0};
const int dy4[4] = {0, 1, 0, -1};
const int dx8[8] = {1, 1, 1, 0, 0, -1, -1, -1};
const int dy8[8] = {0, 1, -1, 1, -1, 0, 1, -1};
const long double pi = 3.141592653589793;

#define addm(X, Y) (X) = ((X) + ((Y) % mod) + mod) % mod
#define inside(y, x, h, w) (0 <= (y) && (y) < (h) && 0 <= (x) && (x) < (w)) ? true : false

//debug
#define DEBUG

#define DUMPOUT cout

#ifdef DEBUG
#define dump(...) DUMPOUT<<#__VA_ARGS__<<" :["<<__FUNCTION__<<":"<<__LINE__<<"]"<<endl; DUMPOUT<<"    "; dump_func(__VA_ARGS__)
#else
#define dump(...)
#endif

void dump_func() {DUMPOUT << endl;};

template <class Head, class... Tail> void dump_func(Head&& head, Tail&&... tail) {
    DUMPOUT << head;
    if (sizeof...(Tail) == 0) DUMPOUT << " ";
    else DUMPOUT << ", ";
    dump_func(std::move(tail)...);
}

//ostream
template<typename T> ostream& operator << (ostream& os, vector<T>& vec) {
    os << "["; for (int i = 0; i<vec.size(); i++) os << vec[i] << (i + 1 == vec.size() ? "" : ", "); os << "]";
    return os;
}

template<typename T, typename U> ostream& operator << (ostream& os, pair<T, U>& pair_var) {
    os << "(" << pair_var.first << ", " << pair_var.second << ")";
    return os;
}

template<typename T, typename U> ostream& operator << (ostream& os, map<T, U>& map_var) {
    os << "[";
    for (auto itr = map_var.begin(); itr != map_var.end(); itr++) {
        os << "(" << itr->first << ", " << itr->second << ")"; itr++;  if(itr != map_var.end()) os << ", "; itr--;
    }
    os << "]";
    return os;
}

template<typename T> ostream& operator << (ostream& os, set<T>& set_var) {
    os << "[";
    for (auto itr = set_var.begin(); itr != set_var.end(); itr++) {
        os << *itr; ++itr; if(itr != set_var.end()) os << ", "; itr--;
    }
    os << "]";
    return os;
}

int n;
double a[25];
double dp[25][200000 + 5];
vector<vector<int>> v(200000 + 5);

/*
a[1] ~ a[n-1] を a[0]に合わせると考えると, a[0] < a[i] (i = 1, 2, .. n - 1) なので
ratio = 1 - x / a[i] を計算すればよく, また今 x = a[0] なので
ratio = 1 - a[0] / a[i] < 1
よって ratio の max の min は1未満に抑えられる
そしてa[i] <= 100000であることから調べるべき数字のmaxは, xが十分大きいとして
ratio = x / a[i] - 1 を考えればよく
x / a[i] - 1 < 1 より, x < 2 * a[i] <= 200000
∴ x < 200000
ratioのmaxのminは1未満に抑えられるから調べるべき数字のminは, xが十分小さいとして
ratio = 1 - x / a[i] を考えればよく
1 - x / a[i] < 1 より 0 < x
∴ 0 < x;
以上から調べるべき数字の範囲は 0 < x < 200000
*/

signed main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> n;
  rep(i, n) cin >> a[i];
  rep2(i, 1, 200000 + 5) {
    for (int j = 1; j * j <= i; j++) {
      if (i % j == 0) {
        v[i].push_back(j);
        if (j != i / j) v[i].push_back(i / j);
      }
    }
  }
  rep(i, n)rep(j, 200000+ 1) dp[i][j] = 1;
  rep(i, n) {
    if (i == 0) {
      rep2(j, 1, 200000 + 1) dp[i][j] = abs(a[i] - j) / a[i];
    }
    else {
      rep2(j, 1, 200000 + 1) {
        double ratio = abs(a[i] - j) / a[i];
        double mn = 1;
        for (auto k : v[j]) {
          mn = min(mn, dp[i - 1][k]);
        }
        if (ratio < mn) dp[i][j] = mn;
        else dp[i][j] = ratio;
      }
    }
  }
  double ans = 1;
  rep2(j, 1, 200000 + 1) ans = min(ans, dp[n - 1][j]);
  cout << fixed << setprecision(20) << ans << endl;

}



Measured memory_bytes: 53888