#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#include <atcoder/all>


using namespace std;
using namespace atcoder;
#define rep(i,m,n,k) for (int i = (int)(m); i < (int)(n); i += (int)(k))
#define rrep(i,m,n,k) for (int i = (int)(m); i > (int)(n); i += (int)(k))
#define ll long long
#define list(T,A,N) vector<T> A(N);for(int i=0;i<(int)(N);i++){cin >> A[i];}
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
template<typename T> map<T,int> Counter(vector<T> X){map<T,int> C;for(auto x:X){C[x]++;}; return C;}
#define all(x) (x).begin(),(x).end()
template<typename T> T sum(vector<T> x){T _tmp=0;for(auto _x:x) _tmp+=_x;return _tmp;}
constexpr ll INF = (1LL << 60);


vector< long long > divisor(long long n) {
  vector< long long > ret;
  for(long long i = 1; i * i <= n; i++) {
    if(n % i == 0) {
      ret.push_back(i);
      if(i * i != n) ret.push_back(n / i);
    }
  }
  sort(begin(ret), end(ret));
  return (ret);
}

int main(){
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    long double N;
    cin >> N;
    cout << fixed << setprecision(10);
    cout << 1/N << endl;
    return 0;


}