Equal Digit Sums

The digit sum of a positive integer $x$ is the sum of its decimal digits. For example, $2$, $11$, and $20$ all have digit sum $2$.

Pick $n$ distinct positive integers whose digit sums are all equal. Write a program that finds the smallest total the picked numbers can have.

The first line contains an integer $n$ ($1 \le n \le 5000$).

Print the minimum possible sum of $n$ distinct positive integers that all have the same digit sum.