#include <bits/stdc++.h>
int N, K;
int a[10005];
int main() {
  scanf("%d%d", &N, &K);
  for (int i = 0; i < N; ++i) {
    scanf("%d", &a[i]);
  }
  double low = 0.0;
  double up = 1000.0;
  double m;
  while (up - low >= 1e-8) {
    m = (up + low) / 2;
    double t = 0.0;
    for (int i = 0; i < N; ++i) {
      if (a[i] > m) {
        t += (a[i] - m) * (100.0 - K) / 100.0;
      } else {
        t -= (m - a[i]);
      }
    }
    if (t >= 0) {
      low = m;
    } else {
      up = m;
    }
  }
  printf("%.9f\n", up);
  return 0;
}
