#include <bits/stdc++.h>
using namespace std;
long double p[105];
int m[105];
int n;
long double tp[105];
long double np[105];
long double rp[105];
priority_queue<pair<long double, int> > q;
int main() {
  scanf("%d", &n);
  for (int i = (0); i < (n); i++) {
    double tmp;
    scanf("%lf", &tmp);
    p[i] = tmp / 100.;
  }
  long double res = n;
  for (int i = (0); i < (n); i++) m[i] = 1;
  long double P = 1;
  for (int i = (0); i < (n); i++) {
    tp[i] = 1 - pow(1 - p[i], m[i]);
    np[i] = 1 - pow(1 - p[i], m[i] + 1);
    rp[i] = np[i] / tp[i];
    P *= tp[i];
    q.emplace(rp[i], i);
  }
  int Z = 0;
  while (1) {
    Z++;
    if (Z % 100 == 0) {
      P = 1;
      for (int i = (0); i < (n); i++) P *= tp[i];
      if (P > 1 - 1e-10) break;
    }
    res += 1 - P;
    int b = q.top().second;
    q.pop();
    P *= rp[b];
    m[b]++;
    tp[b] = np[b];
    np[b] = 1 - pow(1 - p[b], m[b] + 1);
    rp[b] = np[b] / tp[b];
    q.emplace(rp[b], b);
  }
  double tmp = res;
  printf("%.10lf\n", tmp);
}
