#include <bits/stdc++.h>
using namespace std;
const int MAXN = 105;
double p[MAXN], f[MAXN];
struct Node {
  double val;
  int id;
  Node(double a, int b) : val(a), id(b) {}
  bool operator<(const Node& rhs) const { return val < rhs.val; }
};
priority_queue<Node> pq;
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%lf", &p[i]), p[i] /= 100;
  double ans = 1.;
  for (int i = 1; i <= n; i++) pq.push(Node(1e18, i)), f[i] = 1;
  for (int i = 1; i <= 500000; i++) {
    Node t = pq.top();
    pq.pop();
    f[t.id] *= 1 - p[t.id];
    t.val = (1 - f[t.id] * (1 - p[t.id])) / (1 - f[t.id]);
    pq.push(t);
    double cur = 1;
    for (int j = 1; j <= n; j++) cur *= 1 - f[j];
    ans += 1 - cur;
  }
  printf("%.10lf\n", ans);
  return 0;
}
