#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)

int n;
double dp[1000000+1][6+1];

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  cin >> n;
  dp[0][0] = 1.0;

  for (int i = 0; i < n; i++) {
    for (int j = 0; j <= 6; j++) {
      dp[i+1][j] += dp[i][j] * j / 6.0;
      if (j+1 <= 6)
        dp[i+1][j+1] += dp[i][j] * (6 - j) / 6.0;
    }
  }

  cout << fixed << setprecision(12) << dp[n][6] << endl;
  
  return 0;
}