#include <bits/stdc++.h>
using namespace std;
const double EPS = 1e-8;
int main() {
  int n, k;
  scanf("%d%d", &n, &k);
  double r = 1 - k / 100.0;
  vector<double> vp(n);
  for (int i = 0; i < n; ++i) {
    scanf("%lf", &vp[i]);
  }
  sort(vp.begin(), vp.end());
  double low = vp[0], high = vp[n - 1], ans;
  while (high - low > EPS) {
    ans = (high + low) / 2;
    double get = 0, give = 0;
    for (int i = 0; i < n; ++i) {
      if (vp[i] < ans) {
        get += ans - vp[i];
      } else {
        give += vp[i] - ans;
      }
    }
    if (give * r - get > 0) {
      low = ans;
    } else {
      high = ans;
    }
  }
  ans = (high + low) / 2;
  printf("%8lf\n", ans);
  return 0;
}
