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 9.2.1) (judge verdict: Wrong Answer)

#include<stdio.h>

int main(){

int Exp[] = { 1,4,8,9,16,25,27,32,49,64,100,
              121,125,128,144,169,196,225,
              243,256,289,324,343,361,400,
              441,484,512,529,576,625,676,
              729,784,841,900,961
            };
int X;
scanf("%d",&X);

for (int i = 36; i > 0; i--){
    if (Exp[i] <= X){ 
      printf("%d",Exp[i]);
      break;
    }
}
return 0;

}