#include <bits/stdc++.h>
int a[100100];
int main() {
  int i, j, k, l, n;
  double lo, hi, mid, gain, loss, fact;
  while (scanf("%d %d", &n, &k) == 2) {
    for (i = 0; i < n; i++) {
      scanf("%d", &a[i]);
    }
    lo = 0;
    hi = 1000;
    mid = 500;
    j = 0;
    double res;
    for (j = 0; j < 50; j++) {
      mid = (lo + hi) / 2.0;
      res = 0;
      for (i = 0; i < n; i++) {
        if (mid < a[i]) {
          res += (a[i] - mid) * (100 - k) / 100;
        } else if (mid > a[i]) {
          res -= (mid - a[i]);
        }
      }
      if (res < 0)
        hi = mid;
      else
        lo = mid;
    }
    printf("%.7lf\n", mid);
  }
  return 0;
}
