#include <cstdio>
#include <vector>
#include <algorithm>
#include <random>

std::mt19937 rsk(0315);

bool wins(std::vector<int>& A, std::vector<int> &B) {
  std::shuffle(A.begin(), A.end(), rsk);
  std::shuffle(B.begin(), B.end(), rsk);
  size_t N = A.size();
  int a = 0;
  int b = 0;
  for (size_t i = 0; i < N; ++i)
    ++((A[i] > B[i])? a:b);
  return a > b;
}

int main() {
  size_t N;
  scanf("%zu", &N);

  std::vector<int> A(N), B(N);
  for (auto& ai: A) scanf("%d", &ai);
  for (auto& bi: B) scanf("%d", &bi);

  int win = 0;
  for (int i = 0; i < 10000000; ++i)
    if (wins(A, B))
      ++win;

  printf("%.6f\n", win*1e-7);
}