#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  int c = 0;
  bool ok = false;
  while (true){
    for (int a = 1; a <= 9; a++){
      for (int b = a + 1; b <= 9; b++){
        N--;
        if (N == 0){
          cout << a;
          for (int j = 0; j <= c; j++){
            cout << b;
          }
          cout << endl;
          ok = true;
          break;
        }
      }
      if (ok){
        break;
      }
    }
    if (ok){
      break;
    }
    c++;
  }
}