#include <bits/stdc++.h>
using namespace std;
long long spf[101];
long long fac[101];
void sieve() {
  spf[1] = 1;
  for (long long i = 2; i < 101; i++) spf[i] = i;
  for (long long i = 4; i < 101; i += 2) spf[i] = 2;
  for (long long i = 3; i * i < 101; i++) {
    if (spf[i] == i) {
      for (long long j = i * i; j < 101; j += i)
        if (spf[j] == j) spf[j] = i;
    }
  }
}
map<long long, long long> getfactor(long long a) {
  map<long long, long long> m;
  while (a > 1) {
    m[spf[a]]++;
    a /= spf[a];
  }
  return m;
}
long long power(long long x, long long y, long long p) {
  long long res = 1;
  x = x;
  if (x == 0) return 0;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
long long gcd(long long a, long long b) {
  if (a == 0) return b;
  return gcd(b % a, a);
}
long long inverse(long long a, long long p) { return power(a, p - 2, p); }
long long ncr(long long n, long long r, long long p) {
  if (r == 0) return 1;
  return (fac[n] * inverse(fac[r], p) % p * inverse(fac[n - r], p) % p) % p;
}
void solve() {
  long long n, t;
  cin >> n >> t;
  map<long long, long double, greater<long long> > ml;
  map<long long, long double> mr;
  long double ls = 0, rs = 0;
  long double a[n], ans = 0;
  long long te[n];
  for (long long i = 0; i < n; i++) cin >> a[i];
  for (long long i = 0; i < n; i++) {
    cin >> te[i];
    if (te[i] == t)
      ans += a[i];
    else if (te[i] < t) {
      ml[te[i] - t] += a[i];
    } else if (te[i] > t) {
      mr[te[i] - t] += a[i];
    }
  }
  auto it2 = mr.begin();
  for (auto it : ml) {
    long double sum = 0;
    ls = 0, rs = 0;
    ls += (it.first) * (it.second);
    auto it3 = it2;
    while (it2 != mr.end() && rs + ls < 0) {
      it3 = it2;
      rs += (it2->first) * (it2->second);
      sum += it2->second;
      it2++;
    }
    if (rs + ls >= 0) {
      long double gg = rs + ls;
      sum -= gg / it3->first;
      it3->second = gg / it3->first;
      ans += sum + it.second;
    } else {
      long double gg = rs + ls;
      ans += sum + it.second - (gg / it.first);
      break;
    }
    it2 = it3;
  }
  cout << fixed << setprecision(10) << ans << '\n';
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long t = 1;
  while (t--) {
    solve();
  }
}
