#include <bits/stdc++.h>
using namespace std;
const long long maxN = 5e3 + 7, MOD = 1e9 + 7, inf = 1e9, N = 3e5 + 7;
long long n, m, k, help, x[maxN], y[maxN], z[maxN], cnt, maxi, a = -1, b = -1,
                                                               hx, hy, A, B;
long double ans;
int main() {
  cin >> n;
  for (long long i = 1; i <= n; i++) cin >> x[i], maxi = max(maxi, x[i]);
  cin >> m;
  for (long long i = 1; i <= m; i++) cin >> y[i];
  cin >> k;
  for (long long i = 1; i <= k; i++) cin >> z[i];
  cin >> A >> B;
  for (long long i = 1; i <= m; i++) {
    for (long long j = 1; j <= k; j++) {
      hx = B * y[i];
      hy = hx + (A * z[j]);
      if (hx < hy) {
        if (a == -1)
          a = hx, b = hy;
        else if (hx * b > hy * a)
          a = hx, b = hy;
      }
    }
  }
  maxi *= maxi;
  maxi *= a;
  ans = (long double)maxi / (long double)b;
  ans = sqrt(ans);
  return cout << setprecision(13) << ans << "\n", 0;
}
