1174번

1174

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

vector<long long> result;

void dfs(long long number, int newNumber)
{
    for (int i = 0; i < newNumber; i++)
    {
        result.push_back(number * 10 + i);
        dfs(number * 10 + i, i);
    }
}

int main()
{
    int n;
    cin >> n;

    for (int i = 0; i < 10; i++)
    {
        result.push_back(i);
        dfs(i, i);
    }

    if (n > result.size())
    {
        cout << -1 << endl;
    }
    else
    {
        sort(result.begin(), result.end());
        cout << result[n - 1] << endl;
    }
}