#include <bits/stdc++.h>
double a[111];
double p[111];
int main() {
  double t, s, r, rr;
  int i, j, k, n;
  scanf("%d", &n);
  for (i = 0; i < n; i++) {
    scanf("%d", &j);
    p[i] = a[i] = (100 - j) / 100.;
  }
  r = rr = 0;
  for (i = 0; i < 200000; i++) {
    k = 0;
    s = 1 - p[0];
    for (j = 1; j < n; j++) {
      if ((1 - p[j] * a[j]) * (1 - p[k]) > (1 - p[k] * a[k]) * (1 - p[j]))
        k = j;
      s -= s * p[j];
    }
    p[k] *= a[k];
    rr += 1 - s;
    if (rr > r) {
      r += rr;
      rr = 0;
    }
  }
  printf("%.20f", n + r + rr);
}
