#include using namespace std; using ll = long long; #define rep(i, s, t) for (ll i = s; i < (ll)(t); i++) template bool chmin(T &x, T y) { return x > y ? (x = y, true) : false; } template bool chmax(T &x, T y) { return x < y ? (x = y, true) : false; } struct io_setup { io_setup() { ios::sync_with_stdio(false); std::cin.tie(nullptr); cout << fixed << setprecision(15); } } io_setup; vector dv(ll x){ vector res; for(ll i=1;i*i<=x;i++){ if(x%i==0){ res.push_back(i); if(i*i!=x) res.push_back(x/i); } } sort(res.begin(),res.end()); return res; } int main(){ ll n; cin>>n; map mp; auto dfs=[&](auto self,ll x) ->double { if(x==1) return 0; if(mp.count(x)) return mp[x]; double res=x; { auto v=dv(x); reverse(v.begin(),v.end()); vector ct; int m=v.size(); rep(i,0,m){ ll d=x/v.at(i); rep(j,0,i){ if(v.at(j)%v.at(i)==0){ d-=ct.at(j); } } ct.push_back(d); } rep(i,1,m){ res+=self(self,v.at(i))*ct.at(i); } } res/=x-1; return mp[x]=res; }; cout<