#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define rep(i,n) for (int i = 0; i < (n); ++i)
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
const ll INF=1LL<<60;
const int inf=(1<<30)-1;
const int mod=1e9+7;
int dx[8]={1,0,-1,0,-1,-1,1,1};
int dy[8]={0,1,0,-1,-1,1,-1,1};
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;cin >> n;
    vector<vector<double>> dp(n+1,vector<double>(7));
    dp[0][0]=1;
    rep(i,n){
        for(int j=0;j<=6;j++){
            dp[i+1][j]+=dp[i][j]*j/6;
            if(j<6){
                dp[i+1][j+1]+=dp[i][j]*(6-j)/6;
            }
        }
    }
    cout << fixed << setprecision(10) << dp[n][6] << endl;
}