The factorial n! ends in a certain number of trailing zeros. That count grows as n grows but never shrinks. Given a target k, find the smallest non-negative integer n such that n! ends in at least k trailing zeros.
By convention 0! and 1! end in zero trailing zeros. Note that the count of trailing zeros of n! is the number of times 10 divides n!, which is determined by how many factors of 5 appear in the product 1 * 2 * ... * n.
Input format
A single line with one integer k.
Output format
A single integer: the smallest n with at least k trailing zeros in n!.
Constraints
- 0 <= k <= 1000000000