#include <bits/stdc++.h>
using namespace std;
const int N = 210;
int n;
double ans = n, now;
double p[N], f[N], d[N];
void gnew(int id) { d[id] = 1.0 + (1 - f[id]) * p[id] / f[id]; }
int main() {
  ios::sync_with_stdio(false);
  int i, x, T, id;
  cin >> n;
  for (i = 1; i <= n; i++) {
    cin >> x;
    f[i] = p[i] = (double)x / 100.0;
    gnew(i);
  }
  now = 1;
  for (i = 1; i <= n; i++) now *= f[i];
  T = 3e5;
  ans = n;
  while (T > 0) {
    T--;
    ans += 1.0 - now;
    id = 1;
    for (i = 2; i <= n; i++)
      if (d[i] > d[id]) id = i;
    now *= d[id];
    f[id] *= d[id];
    gnew(id);
  }
  printf("%.8lf\n", ans);
  return 0;
}
