#include<bits/stdc++.h>
using namespace std;  
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
#define rep(i,n) for(ll i=0;i<(n);i++)  
#define pii pair<int,int>
#define piii pair<int,pii>
#define mp make_pair
#define pb push_back  
#define ALL(a) (a).begin(),(a).end()
#define FST first
#define SEC second  
const int INF = (INT_MAX/2);
const ll LLINF = (LLONG_MAX/2);
const double eps = 1e-5;
const double PI = M_PI;  
#define DEB cout<<"!"<<endl
#define SHOW(a,b) cout<<(a)<<" "<<(b)<<endl
#define SHOWARRAY(ar,i,j) REP(a,i)REP(b,j)cout<<ar[a][b]<<((b==j-1)?((a==i-1)?("\n\n"):("\n")):(" "))
  
#define DIV 1000000007
typedef vector<ll> Array;
typedef vector<Array> matrix;
typedef tuple<int,int,int> tiii;
#define mt make_tuple

double dp[1000001][7] ={}; // dp[n][used]
int main(){
  int n; cin >> n;
  dp[0][0] = 1.;
  for(int i = 1; i <= n; i++){
    for(int j = 1; j <= 6; j++){
      dp[i][j] += dp[i-1][j-1] * (6.0-double(j-1))/6.0;
      dp[i][j] += dp[i-1][j] * double(j)/6.0;
    }
  }
  cout <<fixed << setprecision(15)<< dp[n][6] << endl;
}