#include <bits/stdc++.h>
using namespace std;
double t;
int main() {
  int n, k;
  cin >> n >> k;
  k = 100 - k;
  double v[100000];
  double low = 0.0, high = 1000;
  for (int i = 0; i < n; i++) {
    cin >> v[i];
  }
  double before = 100;
  while (1) {
    double mid = (high + low) / 2;
    if (fabs(before - mid) < 10e-12) {
      printf("%.10lf\n", mid);
      return 0;
    }
    before = mid;
    double a = 0.0, b = 0.0;
    for (int i = 0; i < n; i++) {
      if (v[i] > mid) {
        a += v[i] - mid;
      } else {
        b += (mid * 100 - 100 * v[i]) / k;
      }
    }
    if (a < b)
      high = mid;
    else
      low = mid;
  }
  return 0;
}
