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<stdio.h>
int main(){
int n,i,j,ans=1;
scanf("%d",&n);
for(i=1;i<40;i++){
j=i;
if(i!=1){
while(j<=n){
j=j*i;
if(j<=n&&j>ans)
ans=j;
}
}
}
printf("%d\n",ans);
return 0;
}
