#include <iostream>
using namespace std;

const string D = "0.1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991";
int main() {
    string s = "";
    int a = 0, n;
    cin >> n;
    for (int i = D.size()-1; i > 1; --i) {
        a = a + ((int)D[i] - 48) * n;
        s = ((char)(a % 10 + 48)) + s;
        a /= 10;
    }
    cout << a << "." << s << endl;
    return 0;
}