#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1);
const int N = (int)1e4 + 7, mod = 1000000007, M = 2e9;
int n;
double k, a[N], st, en = 1000, mid = 2;
bool can() {
  double c = 0, t;
  for (int i = 0; i < n; i++) {
    t = a[i] - mid;
    c += t - (t * k / 100) * (t > 0);
  }
  return c >= 0;
}
int main() {
  cin >> n >> k;
  for (int i = 0; i < n; i++) cin >> a[i];
  while (st < en) {
    mid = (int)(st + en + 1) / 2;
    if (can())
      st = mid;
    else
      en = mid - 1;
  }
  en++;
  while (abs(st - en) > .0000000001) {
    mid = (st + en) / 2;
    if (can())
      st = mid;
    else
      en = mid - .000000001;
  }
  printf("%.9f", st);
  return 0;
}
