#include "iostream"
using namespace std;
const long long int BORDER = 1000000000;

int N;
int up;
long long int down[25]{123456789,101112131,415161718,192021222,324252627,282930313,233343536,373839404,142434445,4647484950,51525354,555657585,960616263,646566676,869707172,737475767,778798081,828384858,687888990,919293949,596979899,1};

int main() {
	cin >> N;
	if (down[0] * N >= BORDER) {
		up = down[0] * N / BORDER;
		down[0] = (down[0] * N) % BORDER;
	}
	for (int i = 1; i < 25; i++) {
		if (down[i] * N >= BORDER) {
			down[i - 1] += down[i] * N / BORDER;
			down[i] = (down[i] * N)%BORDER;
			for (int j = BORDER/10; j >= 1; j /= 10) {
				if (j > down[i]) {
					down[i - 1] *= 10;
				}
			}
		}
	}
	cout << up << ".";
	for (int i = 0; i < 25; i++) {
		cout << down[i];
	}
	cout << "\n";
	return 0;
}