Problem:
Score : 200 points

Problem Statement

You are given a positive integer X.
Find the largest perfect power that is at most X.
Here, a perfect power is an integer that can be represented as b^p, where b is an integer not less than 1 and p is an integer not less than 2.

Constraints

1 ≤ X ≤ 1000

X is an integer.

Input

Input is given from Standard Input in the following format:

X

Output

Print the largest perfect power that is at most X.

Sample Input 1

10

Sample Output 1

9

There are four perfect powers that are at most 10: 1, 4, 8 and 9.
We should print the largest among them, 9.

Sample Input 2

1

Sample Output 2

1

Sample Input 3

999

Sample Output 3

961

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<iostream>
#include<math.h>
#include<string.h>
int main()
{
	int n,a,A;
	while(~scanf("%d",&n))
	{
		int max=1;
		a=sqrt(n);
		for(int i=1;i<=a;i++)
		{
			A=i;
			for(int j=2;j<10;j++)
			{
				A=A*i;
				if(A>max&&A<n)
				max=A;
			}
		}
		printf("%d\n",max,a);
	}
}