#include <bits/stdc++.h>
using namespace std;

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

typedef map<int, int> mii;
typedef pair<int, int> pii;
typedef pair<double,double> pdd;
typedef set<int> si;
typedef set<ll> sll;
typedef vector<int> vi;
typedef vector<pair<int, int > > vii;
typedef vector<ll> vll;
typedef vector<ld> vld;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
typedef vector<vll> vvll;

#define Sort(x) sort(x.begin(),x.end())
#define Reverse(x) reverse(x.begin(),x.end())
#define ABS(a,b) ((a)<(b)?(b)-(a):(a)-(b))

constexpr ll MOD = 1e9+7;
// constexpr int INF = 1<<25;
// constexpr ll  INF = 1LL<<50;

// Returns minimum of a and b.
// If a is less b, a is set to b.
template<typename T>
T checkmin(T& a, T b) {
  if (a > b) {
    a = b;
  }
  return a;
}

// Returns maximum of a and b.
// If a is less b, a is set to b.
template<typename T>
T checkmax(T& a, T b) {
  if (a < b) {
    a = b;
  }
  return a;
}

// a = (a+b)%MOD;
void addmod(ll& a, ll b) {
  a = (a+b)%MOD;
}

// Forward declaration
template <typename T>
void dumpContents(const T& v, const string& msg="");

template <typename T>
void dumpContents(const T& v, const string& msg)
{
  cerr << "### " << msg << " ###\n";
  for (const auto& x : v) {
    cerr << x << " ";
  }
  cerr << endl;
}

struct before_main_function {
  before_main_function() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout<<setprecision(20)<<fixed;
    #define endl "\n"
  }
} before_main_function;

// ========== 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;
}