#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:16777216")
using namespace std;
template <class T>
T abs(T x) {
  return x > 0 ? x : -x;
}
int n;
int m;
double a[10000];
double p;
int good(double x) {
  double x1 = 0, x2 = 0;
  for (int i = 0; i < (n); i++)
    if (a[i] >= x)
      x1 += a[i] - x;
    else
      x2 += x - a[i];
  x1 *= (1 - p);
  return x1 >= x2;
}
int main() {
  cin >> n >> p;
  p /= 100;
  for (int i = 0; i < (n); i++) cin >> a[i];
  double l = 0, r = 1000;
  for (int i = 0; i < (40); i++) {
    double c = (l + r) / 2;
    if (good(c))
      l = c;
    else
      r = c;
  }
  printf("%.6lf\n", (l + r) / 2);
  return 0;
}
