#include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
using namespace std;
using ll = long long;
void chmin(ll &x, ll y) { x = min(x, y); }
void chmax(ll &x, ll y) { x = max(x, y); }
const ll INF = 1e9;
const ll MOD = 1e9 + 7;

int main(){
    double n;
    cin >> n;
    cout << setprecision(10) << 1/n << endl;
}