#include <bits/stdc++.h>
using namespace std;
const int MAXN = 20000;
int n, k;
double a[MAXN];
int check(double aver) {
  double res = 0;
  for (int i = 1; i <= n; i++) {
    if (a[i] < aver)
      res -= (aver - a[i]);
    else
      res += (a[i] - aver) * (100 - k) / 100.0;
  }
  return res >= 0;
}
int main() {
  scanf("%d %d", &n, &k);
  double Max = 0;
  for (int i = 1; i <= n; i++) scanf("%lf", &a[i]), Max = max(Max, a[i]);
  double l = 0, r = Max, mid;
  for (int i = 1; i <= 100; i++) {
    mid = (l + r) / 2;
    if (check(mid))
      l = mid;
    else
      r = mid;
  }
  printf("%.9lf", (l + r) / 2);
  return 0;
}
