//#include <atcoder/all>
//using namespace atcoder;
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i, n) for(int i=0; i<n; i++)
#define REPR(i, n) for(int i=n-1; i>=0; i--)
#define FOR(i, m, n) for(int i=m; i<n; i++)
#define ALL(v) v.begin(), v.end()
#define SIZE(x) int(x.size()) 
#define bit(n) (1LL<<(n))
#define FIX(d) fixed << setprecision(d)
using P = pair<int, int>;
using vvi = vector<vector<int>>;
using vvl = vector<vector<ll>>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = 2e9;
const ll LINF = (1LL<<60);

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  ll k; cin >> k;
  double sum = 0;
  FOR(n,1,10){
    sum += sin(k*n)/pow(n,n);
  }
  cout << FIX(9) << sum << endl;
  return 0;
}