algebra_5

#include <stdio.h>
#include <stack>
#include <math.h>
#include <iostream>
#include <algorithm>
#include <string.h>
#include <string>
#include <set>
#include <memory.h>
#include <vector>
#include <map>
#include <queue>
#include <iomanip>
#include <ctime>
#include <cassert>



#define forn(i, n) for (int i = 0; i < int(n); i++)
#define ll long long
#define mp(a, b) make_pair(a, b)
#define sqr(x) ( (x) * (x) )
#define all(a) a.begin(), a.end()

using namespace std;

int cnt = 0;

void rec(string s, int sz, int pos, int n) {
    if (pos >= sz)
        return;
    for (int i = 0; i < 10; i++) {
        s[pos] = s[s.size() - pos - 1] = '0' + i;
        if (s[0] != '0' && pos == sz - 1)
            cnt++;
        if (cnt == n) {
            cout << s << endl;
            exit(0);
        }
        rec(s, sz, pos + 1, n);
    }
}


int main() {
#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    int t = 1, len = 1;
    int n;
    cin >> n;
    while (1) {
        int sz = (int)(len / 2.0 + 0.5);
        string s = "";
        forn (i, len)
            s += '0';
        rec(s, sz, 0, n);
        len++;
    }

    return 0;
}