#include <bits/stdc++.h>
using namespace std;
int n, k;
double matrix[10009];
string BI(double x) {
  int a = 0, b = 0;
  double up = 0, dn = 0;
  for (int i = 0; i < n; ++i)
    if (matrix[i] > x) {
      ++a;
      up += matrix[i];
    } else {
      ++b;
      dn += matrix[i];
    }
  double part1 = (up - a * x) * (100 - k) / 100.0;
  double part2 = x * b - dn;
  if (fabs(part1 - part2) < 0.000001) {
    dn += (part2 + part2) / 2.0;
    if (b == 0) b = 1;
    dn /= (double)b;
    cout.precision(7);
    cout << fixed << dn;
    return "YES";
  } else {
    if (part1 < part2)
      return "<";
    else
      return ">";
  }
}
int main() {
  cin >> n >> k;
  for (int i = 0; i < n; ++i) cin >> matrix[i];
  if (n == 1) {
    cout << matrix[0];
    return 0;
  }
  int YES = 0;
  for (int i = 0; i < n; ++i) {
    if (i == 0)
      ++YES;
    else if (matrix[i] == matrix[i - 1])
      ++YES;
  }
  if (YES == n) {
    cout << matrix[0];
    return 0;
  }
  double l = 0, r = 1000, x = (l + r) / 2.0;
  string bi = BI(x);
  while (bi != "YES") {
    if (bi == "<") {
      r = x;
      x = (l + r) / 2.0;
      bi = BI(x);
    } else {
      l = x;
      x = (l + r) / 2.0;
      bi = BI(x);
    }
  }
  return 0;
}
