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.

Examples

Input

10


Output

9


Input

1


Output

1


Input

999


Output

961
#include<bits//stdc++.h>
int main(){
	int x, max = 1,p;
	scanf("%d", &x);
	if (x != 1) {
		for (int i = 2; i < x; ++i) {
			p = 2;
			while (pow(i, p) <= x)
			{
				max = fmax(max, pow(i, p));
				++p;
			}
		}
	}
	else max = 1;
	printf("%d", max);
}