#include <bits/stdc++.h>
using namespace std;
int n, k, a[200002];
int main() {
  cin >> n >> k;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  double l = 0.0, r = 1000.0;
  for (int i = 0; i < 200; i++) {
    double m = (l + r) / 2.0;
    double u = 0.0, d = 0.0;
    for (int j = 0; j < n; j++) {
      u += max(0.0, a[j] - m);
      d -= min(0.0, a[j] - m);
    }
    u *= (100.0 - k) / 100.0;
    if (u < d)
      r = m;
    else
      l = m;
  }
  printf("%.6f\n", l);
}
