#include <bits/stdc++.h>
using namespace std;
double n, m, h, x, r1, p1, p2 = 1e9, A, B;
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> x;
    r1 = max(r1, x);
  }
  cin >> m;
  for (int i = 1; i <= m; i++) {
    cin >> x;
    p1 = max(p1, x);
  }
  cin >> h;
  for (int i = 1; i <= h; i++) {
    cin >> x;
    p2 = min(p2, x);
  }
  cin >> A >> B;
  printf("%.9lf", sqrt(r1 * r1 / (A * p2 / B / p1 + 1)));
  return 0;
}
