#include <bits/stdc++.h>

constexpr int N = (1 + 8) * 8 / 2;

int main() {
    std::cin.tie(nullptr)->sync_with_stdio(false);
    int n; std::cin >> n;
    auto [d, r] = std::div(n - 1, N);
    for (int i = 0, a = 1; a <= 9; ++a)
        for (int b = a + 1; b <= 9; ++b, i += 1) {
            if (i == r)  {
                std::cout << a << std::string(d + 1, b + '0') << "\n";
                return 0;
            }
        }
    return 0;
}