#include<bits/stdc++.h>
using namespace std;

string s = "1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991";



string pluss(string a, string b, bool flag = false){
	if (!flag){
		reverse(a.begin(), a.end());
		reverse(b.begin(), b.end());
	}
	if (a.size() > b.size()){
		swap(a, b);
	}
	string ans;
	ans.clear();
	long long int want = 0;
	for (int i = 0; i < a.size(); i++){
		long long int val = a[i] - '0';
		val += b[i] - '0';
		val += want;
		want = val / 10LL;
		val %= 10LL;
		ans.push_back(val + '0');
	}
	for (int j = a.size(); j < b.size(); j++){
		long long int val = 0;
		val += b[j] - '0';
		val += want;
		want = val / 10LL;
		val %= 10LL;
		ans.push_back(val + '0');
	}
	while (want){
		ans.push_back(want % 10 + '0');
		want /= 10;
	}
	if (!flag){
		reverse(ans.begin(), ans.end());
	}
	if (ans.size() == 0)ans = "0";
	return ans;
}
string mult(string a, string b, bool flag = false){
	if (!flag){
		reverse(a.begin(), a.end());
		reverse(b.begin(), b.end());
	}
	string ans = "0";
	string pas;
	string kari;
	pas.clear();
	for (int i = 0; i < b.size(); i++){
		long long int bb = b[i] - '0';
		long long int tmp = 0;
		kari = pas;
		for (int j = 0; j < a.size(); j++){
			long long int val = (long long int)(a[j] - '0')*bb;
			val += tmp;
			tmp = val / 10LL;
			val %= 10LL;
			kari.push_back(val + '0');
		}
		while (tmp){
			kari.push_back((tmp % 10LL) + '0');
			tmp /= 10LL;
		}
		ans = pluss(ans, kari, true);
		//end
		pas.push_back('0');
	}
	if (!flag){
		reverse(ans.begin(), ans.end());
	}
	if (ans.size() == 0)ans = "0";
	return ans;
}
string minuss(string a, string b){
	reverse(b.begin(), b.end());
	reverse(a.begin(), a.end());
	while (a.size()>b.size()){
		b.push_back('0');
	}
	while (a.size()<b.size()){
		a.push_back('0');
	}
	bool carry = false;
	for (int i = 0; i<a.size(); i++){
		if (a[i] != '0'&&carry){
			a[i]--;
			carry = false;
		}
		if (a[i] == '0'&&carry){
			a[i] = '9';
		}
		if (a[i] >= b[i]){
			a[i] = (a[i] - '0') - (b[i] - '0') + '0';
		}
		else{
			a[i] = (10 + (a[i] - '0') - (b[i] - '0')) + '0';
			carry = true;
		}
	}
	while (a.size()>1 && a.back() == '0'){
		a.pop_back();
	}
	reverse(a.begin(), a.end());
	return a;
}

int main(){
	string f;
	cin >> f;
	s = mult(s, f);
	string ansA = s.substr(0,  s.size()-190);
	string ansB = s.substr(-190 + s.size(), 190);
	while (ansB.size() && ansB.back() == '0'){
		ansB.pop_back();
	}
	if (ansA.size() == 0){
		ansA.push_back('0');
	}
	cout << ansA << "." << ansB << endl;
	return 0;
}