#include <bits/stdc++.h>
using namespace std;
#define int long long
#define INF (int)1e18
#define f first
#define s second

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

void num(int a, int b, int dig){
    cout<<a;
    for (int i=1; i<dig; i++)
    cout<<b;
}

void Solve() 
{
    int n; cin>>n;
    
    for (int dig = 2; ; dig++){
        //increase b first then 
        for (int a=1; a<10; a++){
            for (int b=a+1; b<10; b++){
                n--;
                if (n==0){
                    num(a, b, dig);
                    return;
                }
            }
        }
    }
}

int32_t main() 
{
    auto begin = std::chrono::high_resolution_clock::now();
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;
   // cin >> t;
    for(int i = 1; i <= t; i++) 
    {
        //cout << "Case #" << i << ": ";
        Solve();
    }
    auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
    return 0;
}