hdu 5108 Alexandra and Prime Numbers (水题，暴力）
Problem Description
Alexandra has a little brother. He is new to programming. One day he is solving the following problem: Given an positive integer N, judge whether N is prime. The problem above is quite easy, so Alexandra gave him a new task: Given a positive integer N, find the minimal positive integer M, such that N/M is prime. If such M doesn't exist, output 0. Help him!
Input
There are multiple test cases (no more than 1,000). Each case contains only one positive integer N. is no more than 100.
Output
For each case, output the requested M, or output 0 if no solution exists.
Sample Input
3
4
5
6
Sample Output
1
2
1
2
找出n的最大素因子，在用n除以最大素因子就行了。注意1无素因子，应该特殊考虑。