说明：  设n是一个k（1≤k≤80）位的十进制正整数。 问题：对于给定的任意整数n，编程求解满足p3+p2+3p≤n的p的最大值。
(Set n is a k (1 ≤ k ≤ 80)-bit decimal integer. Question: For a given any integer n, programming to solve the meet p3+ p2+3 p ≤ n the p maximum.)