#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define ll long long #define ld long double #define EPS 0.0000000001 #define INF 1e9 #define LINF (ll)INF*INF #define MOD 1000000007 #define rep(i,n) for(int i=0;i<(n);i++) #define loop(i,a,n) for(int i=a;i<(n);i++) #define all(in) in.begin(),in.end() #define shosu(x) fixed< vi; typedef vector vs; typedef pair pii; typedef vector vp; int gcd(int a, int b){ if(b==0) return a; return gcd(b,a%b); } int lcm(int a, int b){ return a/gcd(a,b)*b; } vector memo(30,-1); int n; double f(int k){ if(k >= n)return 0; if(memo[k] != -1)return memo[k]; double ret = 1; loop(i,1,7)ret += f(k+i)/6; return memo[k] = ret; } signed main(void) { cin >> n; cout << shosu(5) << f(0) << endl; }