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 (GCC 5.4.1) (judge verdict: Runtime Error)

#include <stdio.h>




int maxf(int a[]){
	int max = a[0];
	for(int i=1;i<100;i++){
		if(a[i] > max) max = a[i];

	}
	return max;
}

int main(void){

	int n, k = 2;

	scanf("%d", &n);

	if (n == 1) printf("1\n");

	int a[100] = {0,0};

	for(int t=2;t < n-1;t++){
		int i = t;
		while(n>i) i=i*t;
		a[t] =i/t;
	}

	printf("%d\n",maxf(a));


	return 0;

}