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

int main() {
  int64_t N;
  cin >> N;
  int M = (N - 1) / 36;
  int K = (N - 1) % 36;
  vector<int> vec;
  vec = {12, 13, 14, 15, 16, 17, 18, 19, 23, 24, 25, 26, 27, 28, 29, 34, 35, 36, 37, 38, 39, 45, 46, 47, 48, 49, 56, 57, 58, 59, 67, 68, 69, 78, 79, 89} ;
  cout << (vec.at(K)) / 10 ;
  for (int i = 0; i < M + 1; i++) {
      cout << (vec.at(K)) % 10 ;
  }
}