#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>

using namespace std;

int main() {
  int n;
  cin >> n;

  vector<double> dp(1 << 6);
  dp[0] = 1;
  for (int i = 0; i < n; i++) {
    vector<double> dp2(1 << 6);
    for (int j = 0; j < 1 << 6; j++) {
      for (int k = 0; k < 6; k++) {
        dp2[j | 1 << k] += dp[j] / 6;
      }
    }
    dp = dp2;
  }

  printf("%.20f\n", dp[(1 << 6) - 1]);
}