#include <algorithm>
#include <iostream>
#include <vector>

int main() {
    using namespace std;
    int n;
    cin >> n;
    string d = "001234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991";
    reverse(d.begin(), d.end());
    string ans = "";
    int c = 0;
    for (char di : d) {
        int m = (di - '0') * n + c;
        ans.push_back('0' + (m % 10));
        c = m / 10;
    }
    ans.insert(ans.begin() + 190, '.');
    while (ans.back() == '0') { ans.pop_back(); }
    if (ans.back() == '.') { ans.push_back('0'); }
    reverse(ans.begin(), ans.end());
    cout << ans << endl;
}