#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using pii = pair<int, int>;

int main() {
  int n;
  cin >> n;
  
  double ans = 0.0;
  for (int i = n - 1; i > 0; i--) {
    double p = (double)n / i;
    ans += p;
  }

  printf("%.10f\n", ans);
  return 0;
}

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)

// 最大公約数
ll gcd(ll a, ll b) { return (a % b)? gcd(b, a % b): b; }
ll gcd(ll a, ll b, ll c){ return gcd(a, gcd(b,c)); }

int main(){
    int N;cin >> N;

    ll result = 0;
    rep(i,N){ 
        int temp;
        cin >> temp; 

        if(temp>10){
            result += temp-10;
        }
    }

    cout << result << endl;
}