#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

string D = "0.1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991";

string func( string s ) {
    string ret;
    int carry = 0;
    for ( int i = D.length()-1; i >= 0; i-- ) {
        if ( D[i] == '.' ) { ret += '.'; continue; }
        int a = D[i]-'0' + s[ s.length()-1 - (D.length()-1-i) ]-'0';    
        a += carry;
        ret += '0' + a%10;
        carry = a/10;
    }
    int i = s.length()-1 - D.length();
    while ( i >= 0 || carry > 0 ) {        
        int a = ( i >= 0 ? s[i]-'0' : 0 ) + carry;
        ret += '0' + a%10;        
        carry = a/10;
        i--;
    }

    reverse( ret.begin(), ret.end() );
    return ret;
}

int main() {
    
    int N;
    cin >> N;
    string s = D;
    for ( int i = 1; i < N; i++ ) {
        s = func( s );
    }
    cout << s << endl;
    return 0;
}