#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;

int main(void) {
    int n;
    cin >> n;
    n--;
    vector<int> koho;
    for(int i = 1; i <= 9; i++) {
        for(int j = i + 1; j <= 9; j++) {
            koho.push_back(10 * i + j);
        }
    }
    int m = koho.size();
    int x = n / m;
    int y = n % m;
    cout << koho[y];
    for(int i = 0; i < x; i++) cout << koho[y] % 10;
    cout << endl;
    return 0;
}