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: Accepted)


#include <stdio.h>

int main(){
    int x, i, j, k, n, max=0;

    scanf("%d", &x);

    for(i=1; i<=x; i++){
        n=i;
        for(j=0; j<x; j++){
            n *= i;
            if(n > x)
                break;
            if(max < n)
                max = n;
        }
    }

    printf("%d\n", max);

    return 0;
}