#include <bits/stdc++.h>
using namespace std;

#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0)

const int maxN = 1e5 + 1;

int main() {
  FASTIO;
  int k;
  cin >> k;
  vector<string> v;
  //adj[0].push_back(1), adj[1].push_back(0), adj[1].push_back(2), adj[2].push_back(1);
  v.push_back("1"), v.push_back("2"), v.push_back("3"), v.push_back("4"), v.push_back("5"), v.push_back("6"), v.push_back("7");
  v.push_back("8"), v.push_back("9");
  int wtf = 0;
  string now = "";
  for (int i = 10; i < maxN; i++) {
    now = v[wtf];
    int n = (int) now.size();
    int aux = (now[n - 1] - '0');
    string sos = now;
    aux--;
    int d = (now[n - 2] - '0');
    if (aux >= 0) {
      now += (aux + '0');
      v.push_back(now);
    }
    aux++;
    now = sos;
    if (aux <= 9) {
      now += (aux + '0');
      v.push_back(now);
    }
    aux++;
    now = sos;
    if (aux <= 9) {
      now += (aux + '0');
      v.push_back(now);
    }
    wtf++;
  }
  cout << v[k - 1] << endl;
  return 0;
}