#include <bits/stdc++.h>
using namespace std;
int main() {
  double n, x, m, y, k, z, A, B;
  cin >> n;
  double maxR1 = INT_MIN;
  double maxP1 = INT_MIN;
  double minP2 = INT_MAX;
  for (int i = 0; i < n; i++) {
    cin >> x;
    maxR1 = max(maxR1, x);
  }
  cin >> m;
  for (int i = 0; i < m; i++) {
    cin >> y;
    maxP1 = max(maxP1, y);
  }
  cin >> k;
  for (int i = 0; i < k; i++) {
    cin >> z;
    minP2 = min(minP2, z);
  }
  cin >> A >> B;
  double R2 = sqrt((maxR1 * maxR1) / (((A * minP2) / (B * maxP1)) + 1.00));
  printf("%.12f\n", R2);
}
