#include "bits/stdc++.h"
#include <unistd.h>
using namespace std;
#include "atcoder/all"
using namespace atcoder;
using i64 = long long;
using i128 = __int128_t;
using u64 = unsigned long long;
using ld = long double;
using i_i = pair<int, int>;
using l_l = pair<i64, i64>;
using d_d = pair<double, double>;
using s_s = pair<string, string>;
using i_i_i = tuple<int, int, int>;
using i_i_i_i = tuple<int, int, int, int>;
using l_l_l = tuple<i64, i64, i64>;
using l_l_l_l = tuple<i64, i64, i64, i64>;
using _bool = int;
#define rep(i, n) for(int i = 0; i < n; i++)
#define ifbit(n,k) ((n>>k)&1) //if kth bit of n is on then true (sitakara, 0-indexed)
#define zpad(i) cout << setfill('0') << setw(i)
#define dout cout << fixed << setprecision(10)
#define douts(i) cout << fixed << setprecision(i) << scientific
#define pcnt __builtin_popcount
constexpr int INF = 2147483647;
constexpr i64 I64F = 9223372036854775807;
template <class T> bool chmax(T &l, const T &r) { if (l < r) { l = r; return true; } return false; }
template <class T> bool chmin(T &l, const T &r) { if (l > r) { l = r; return true; } return false; }
template <class T> pair<int, bool> ub(const vector<T> &v, const T &key) { int ind = upper_bound(v.begin(), v.end(), key) - v.begin(); if (ind == (int)v.size()) return make_pair(0, false); return make_pair(ind, true); }
template <class T> pair<int, bool> rub(const vector<T> &v, const T &key) { int ind = upper_bound(v.rbegin(), v.rend(), key, [](const T &l, const T &r) { return l > r; }) - v.rbegin(); if (ind == (int)v.size()) return make_pair(0, false); return make_pair((int)v.size() - 1 - ind, true); }
template <class T> pair<int, bool> lb(const vector<T> &v, const T &key) { int ind = lower_bound(v.begin(), v.end(), key) - v.begin(); if (ind == (int)v.size()) return make_pair(0, false); return make_pair(ind, true); }
template <class T> pair<int, bool> rlb(const vector<T> &v, const T &key) { int ind = lower_bound(v.rbegin(), v.rend(), key, [](const T &l, const T &r) { return l > r; }) - v.rbegin(); if (ind == (int)v.size()) return make_pair(0, false); return make_pair((int)v.size() - 1 - ind, true); }

std::ostream &operator<<(std::ostream &dest, __int128_t value) {
  std::ostream::sentry s(dest);
  if (s) {
    __uint128_t tmp = value < 0 ? -value : value;
    char buffer[128];
    char *d = std::end(buffer);
    do {
      --d;
      *d = "0123456789"[tmp % 10];
      tmp /= 10;
    } while (tmp != 0);
    if (value < 0) {
      --d;
      *d = '-';
    }
    int len = std::end(buffer) - d;
    if (dest.rdbuf()->sputn(d, len) != len) {
      dest.setstate(std::ios_base::badbit);
    }
  }
  return dest;
}

int main() {
    // 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9
    // 8 , 7 , 6 , 5 , 4 , 3 , 2 , 1, 
    //  9 * 4 = 36
    int n; cin >> n;
    n--;
    int d = n / 36;
    int k = n % 36;
    vector<string> v(36);
    int i = 0;
    for (int a = 1; a <= 9; a++) {
        for (int b = a + 1; b <= 9; b++) {
            int x = a * 10 + b;
            v[i++] = to_string(x);
        }
    }
    auto s = v[k];
    rep(i, d) {
        s += s.back();
    }
    cout << s << endl;
}