#include <bits/stdc++.h>
#include<iostream>
#include<iomanip>
#include<string>
#include<algorithm>
#include<vector>
#include<set>
#include<list>
#include<queue>
#include<math.h>
#include<bitset>
using ll = long long;
using namespace std;

string D = "0.1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991";

string cal(int n){
    string ans = "";
    int up = 0;
    for (int i = D.size()-1; i >= 0; i--){
        if (D[i] != '.'){
            int a = D[i] - '0';
            a *= n;
            a += up;
            up = a/10;
            a -= up*10;
            ans = to_string(a) + ans;
        } else ans = '.' + ans;
        
    }
    return ans;
}

int main()
{
    int n;
    cin >> n;
    cout << cal(n) << endl;
}