Series

Write all the natural numbers from $n$ to $m$ (inclusive) in a row, without any separators, forming a series of decimal digits.

For example, if $n = 98$ and $m = 102$, this series is 9899100101102.

Then sort all the digits in non-increasing order: the greatest digits first, then the next greatest, and so on.

For the example above, the sorted series is 9998211110000.

Given the natural numbers $n$, $m$, and $k$, determine which digit is at the $k$-th position of the sorted series.

Three natural numbers $n$, $m$, and $k$, separated by spaces. ($0 < n < 10^9$, $0 < m < 10^9$, $m \ge n$, $0 < k < 10^9$)

Output the digit at the $k$-th position of the sorted series. If the length of the series is less than $k$, output the single word NAV.