#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const double eps = 1e-8;
const int mod = 1000000007;
const double pi = acos(-1.0);
inline void gn(long long& x) {
  int sg = 1;
  char c;
  while (((c = getchar()) < '0' || c > '9') && c != '-')
    ;
  c == '-' ? (sg = -1, x = 0) : (x = c - '0');
  while ((c = getchar()) >= '0' && c <= '9') x = x * 10 + c - '0';
  x *= sg;
}
inline void gn(int& x) {
  long long t;
  gn(t);
  x = t;
}
inline void gn(unsigned long long& x) {
  long long t;
  gn(t);
  x = t;
}
long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }
long long powmod(long long a, long long x, long long mod) {
  long long t = 1ll;
  while (x) {
    if (x & 1) t = t * a % mod;
    a = a * a % mod;
    x >>= 1;
  }
  return t;
}
const int maxn = 1e4 + 5;
double a[maxn];
int n, k;
bool check(double v) {
  double lft = 0.0;
  for (int i = (1); i <= (n); i++) {
    if (a[i] - v > eps)
      lft += (a[i] - v) * (100.0 - 1. * k) / 100.0;
    else if (v - a[i] > eps)
      lft -= (v - a[i]);
  }
  return lft > eps;
}
int main() {
  cin >> n >> k;
  for (int i = (1); i <= (n); i++) cin >> a[i];
  double l = 0, r = 1111;
  for (int i = (1); i <= (100); i++) {
    double mid = (l + r) / 2.0;
    if (check(mid))
      l = mid + eps;
    else
      r = mid - eps;
  }
  printf("%.20lf\n", l);
  return 0;
}
