题目：将一个正整数分解质因数。例如：输入90,打印出90=2*3*3*5。

程序分析：对n进行分解质因数，应先找到一个最小的质数k，然后按下述步骤完成：

(1)如果这个质数恰等于n，则说明分解质因数的过程已经结束，打印出即可。

(2)如果n<>k，但n能被k整除，则应打印出k的值，并用n除以k的商,作为新的正整数你n,重复执行第一步。

(3)如果n不能被k整除，则用k+1作为k的值,重复执行第一步。

-Subject: a positive integer factorization. For example: enter 90, print out 90=2*3*3*5.

Program analysis: the N decomposition of the quality factor, should first find a minimal prime number k, then complete the following steps:

(1) if the prime exactly equal to N, then the prime factor decomposition process has ended, you can print out.

(2) if n<>k but n of the can is divisible by K, you should print out the K value, and divide by N K, you are n a positive integer as a new, repeat the first step.

(3) if n is not divisible by K, with k+1 as the value of K, repeat the first step.