#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <numeric>
#include <utility>
#include <tuple>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;
using P = pair<int, int>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; PPPPP(__VA_ARGS__); cerr << endl; } while(false)
template<typename T> void PPPPP(T t) { cerr << t; }
template<typename T, typename... S> void PPPPP(T t, S... s) { cerr << t << ", "; PPPPP(s...); }
#else
#define dump(...) do{ } while(false)
#endif
template<typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template<typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v(ts...))>(a, make_v(ts...)); }
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> void print(T a) { cout << a << endl; }
template<typename T, typename... Ts> void print(T a, Ts... ts) { cout << a << ' '; print(ts...); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
// clang-format on

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    string s = "1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991";
    reverse(s.begin(), s.end());
    int N;
    cin, N;
    int digit = 300;
    vector<int> d(digit, 0);
    REP(i, 0, s.size()) {
        d[i] = s[i] - '0';
    }
    vector<int> a;
    while (N) {
        a.push_back(N % 10);
        N /= 10;
    }
    vector<int> ans(digit, 0);
    REP(i, 0, a.size()) {
        REP(j, 0, digit - 10) {
            ans[i + j] += a[i] * d[j];
        }
    }
    REP(i, 0, digit - 1) {
        if (ans[i] >= 10) {
            ans[i + 1] += ans[i] / 10;
            ans[i] %= 10;
        }
    }
    bool noz = false;
    reverse(ans.begin(), ans.end());
    REP(i, 0, digit) {
        if (ans[i] != 0) {
            noz = true;
        }
        if (noz) {
            cout << ans[i];
        }
        if (i == 109) {
            if (!noz) {
                cout << 0;
            }
            cout << '.';
        }
    }
    cout << endl;

    return 0;
}