#include <bits/stdc++.h>
using namespace std;
int n, m, k;
vector<int> x, y, z;
int A, B;
int main() {
  while (scanf("%d", &n) >= 1) {
    x.resize(n);
    for (int i = 0; i < n; i++) scanf("%d", &x[i]);
    sort((x).begin(), (x).end());
    scanf("%d", &m);
    y.resize(m);
    for (int i = 0; i < m; i++) scanf("%d", &y[i]);
    sort((y).begin(), (y).end());
    scanf("%d", &k);
    z.resize(k);
    for (int i = 0; i < k; i++) scanf("%d", &z[i]);
    sort((z).begin(), (z).end());
    scanf("%d%d", &A, &B);
    double r2 = x.back() * sqrt(B * y.back() * 1.0 / (B * y.back() + A * z[0]));
    printf("%.20lf\n", r2);
  }
  return 0;
}
