#include <bits/stdc++.h>
using namespace std;
int n, k;
double V[10000];
bool TRY(double how) {
  double BAL = 0;
  for (int i = 0; i < n; ++i)
    if (V[i] < how)
      BAL -= how - V[i];
    else
      BAL += ((V[i] - how) * (100 - k)) / 100;
  return BAL >= 0;
}
int main() {
  int i, j;
  cin >> n >> k;
  for (i = 0; i < n; ++i) cin >> V[i];
  double L = 0, R = 1010, M;
  for (int Q = 0; Q < 100; ++Q) {
    M = (L + R) / 2;
    if (TRY(M))
      L = M;
    else
      R = M;
  }
  printf("%.12lf\n", (L + R) / 2);
  return 0;
}
