#include <bits/stdc++.h>
using namespace std;
int n;
int a[10010];
double k, x;
const double inf = 1e-7;
int main() {
  cin >> n >> k;
  k /= 100;
  for (int i = 0; i < n; i++) scanf("%d", a + i);
  double low, high, out, in;
  low = 0, high = 1010;
  while (high - low > inf) {
    out = in = 0;
    x = (high + low) / 2;
    for (int i = 0; i < n; i++) {
      double t = a[i] - x;
      if (t < 0)
        in += -t;
      else
        out += t;
    }
    out *= (1 - k);
    if (fabs(out - in) < inf)
      break;
    else if (out > in)
      low = x;
    else
      high = x;
  }
  printf("%.7f\n", x);
  return 0;
}
