#include "bits/stdc++.h"
#define REP(i,n,N) for(int i=(n); i<(N); i++)
#define RREP(i,n,N) for(int i=(N-1); i>=n; i--)
#define CK(n,a,b) ((a)<=(n)&&(n)<(b))
#define ALL(v) (v).begin(),(v).end()
#define p(s) cout<<(s)<<endl
#define p2(a,b) cout<<(a)<<" "<<(b)<<endl
#define v2(T) vector<vector<T>>
typedef long long ll;
using namespace std;
const ll inf=1e18+7;

ll N;
double dp[1000010][10];
int main() {
    cin>>N;
    dp[0][0]=1;
    REP(i,0,N){
        REP(j,0,7){
            dp[i+1][j] += dp[i][j]*j/6;
            dp[i+1][j+1] += dp[i][j]*(6LL-j)/6;
        }
    }
    printf("%.10lf\n", dp[N][6]);
    return 0;
}