#include <iostream>
#include <algorithm>
#include <vector>
#include <deque>
#include <queue>
#include <set>
#include <map>
#include <limits>
#include <cmath>
#include <iomanip>
#include <functional>
#include <random>
#include <set>
#include <atcoder/string>
#include <unordered_map>
#include <climits>
#include <atcoder/lazysegtree>

using namespace std;
using ll = long long;
using namespace atcoder;

int solve()
{
    ll N;
    cin >> N;
    vector<pair<ll,ll>> pairs;
    for(int a = 1;a <= 9;a++ ){
        for(int b = a+1;b <= 9;b++){
            pairs.push_back({a,b});
        }
    }
    N--;
    ll index = N%pairs.size();
    ll count = N/pairs.size() + 1;
    cout << pairs[index].first;
    for(int i = 0;i < count;i++){
        cout << pairs[index].second;
    }
    cout << endl;
    return 0;
}
int main()
{
    // ll T;
    // cin >> T;
    // while (T--)
    // {
        solve();
    // }
    // cout << flush;
    return 0;
}