#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)



#define rrep(i,a,b) for(int i=a;i>=b;i--)
int N;
string D = "0.1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991";
//-----------------------------------------------------------------
string sum(string a, string b) {
	int da = a.find('.');
	int db = b.find('.');
	int d = max(da, db);

	if (da < db)
		rep(i, 0, db - da) a = "0" + a;
	else if(da > db)
		rep(i, 0, da - db) b = "0" + b;

	int na = a.length();
	int nb = b.length();
	int n = max(na, nb);
	
	if (na < nb)
		rep(i, 0, nb - na) a = a + "0";
	else if (na > nb)
		rep(i, 0, na - nb) b = b + "0";

	string ret = "";
	int z = 0;
	rrep(i, n - 1, 0) {
		if (a[i] == '.') {
			ret = "." + ret;
			continue;
		}

		int aa = a[i] - '0';
		int bb = b[i] - '0';

		char c = '0';

		int cc = (aa + bb + z) % 10;
		c += cc;

		z = (aa + bb + z) / 10;

		ret = c + ret;
	}

	if (z != 0) {
		char c = '0' + z;
		ret = c + ret;
	}

	return ret;
}
//-----------------------------------------------------------------
int main() {
	cin >> N;

	string ans = D;
	rep(i, 1, N) ans = sum(ans, D);
	cout << ans << endl;
}