#include <bits/stdc++.h>
using namespace std;
long long n, k, a[10000];
bool lss(long long x) {
  long long sm = 0, sm2 = 0;
  for (int i = 0; i < n; i++) {
    sm += (a[i] > x) * (a[i] - x);
    sm2 += (a[i] < x) * (x - a[i]);
  }
  return sm * k / 100 > sm2;
}
long long bs() {
  long long l = 0, h = 10000000000ll, c;
  while (l <= h) {
    if (lss(c = (l + h) / 2))
      l = c + 1;
    else
      h = c - 1;
  }
  return h;
}
int main() {
  cin >> n >> k;
  k = 100 - k;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    a[i] *= 10000000ll;
  }
  printf("%.7f", bs() / 10000000.0);
  return 0;
}
