#include <iostream>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

// ========== end of template ==========
constexpr int N_MAX = 1e6;
constexpr int KINDS = 6;
// [i][k]
//    i番目までで (0-indexed), k種類揃っている確率
ld dp[N_MAX+1][KINDS+1] = {0.0};

int main(int argc, char** argv) {
  int N;
  cin >> N;

  dp[0][0] = 1.0;
  for (int i=1; i<=N; i++) {
    for (int k=1; k<=KINDS; k++) {
      dp[i][k] = dp[i-1][k]*double(k)/6.0 +
	         dp[i-1][k-1]*double(6-(k-1))/6.0;
    }
  }

  cout << dp[N][6] << endl;

  return 0;
}