Consider a positive integer . Let be the number of positive integer divisors of . For example, if then , since the divisors of are and .
Now, consider a positive integer . What is the smallest value of such that ?
The single line of input contains a single integer (). This is the of the statement above.
Output a single integer, which is the smallest value of such that , or if no such value of exists.
15625
25
64000000
20
65536
-1
