#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9;
const long double EPS = 1e-8;
const long double PI = acos(-1.0);
const int MAXN = 110;
const int MAXM = MAXN * MAXN;
long double p[MAXM];
long double q[MAXM];
long double a[MAXN];
int main() {
  int n;
  scanf("%d", &n);
  long double s = 0;
  for (int i = int(0); i < int(n); ++i) {
    int x;
    scanf("%d", &x);
    p[i] = x * 0.01L;
    q[i] = 1 / p[i];
    s += q[i];
  }
  for (int j = int(0); j < int(n); ++j) a[j] = 1;
  long double sum = 0;
  for (int i = int(0); i < int(500000); ++i) {
    long double bt = 1;
    for (int j = int(0); j < int(n); ++j) {
      bt *= (1 - a[j]);
    }
    sum += (1 - bt);
    int mj = 0;
    if (i < n) {
      mj = i;
    } else {
      bt = -INF;
      for (int j = int(0); j < int(n); ++j) {
        long double na = (1 - a[j] * (1 - p[j])) / (1 - a[j]);
        if (na > bt) {
          bt = na;
          mj = j;
        }
      }
    }
    a[mj] *= (1 - p[mj]);
  }
  cout << fixed << setprecision(25) << sum << '\n';
  return 0;
}
