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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <cmath>
using namespace std;
int main(){
    int x;
    cin >> x;
    int ans = 0;
    for(int b = 1; b < 33; b++)
    {
        for(int p = 2; p < 11; p++)
        {
            int bp = pow(b,p);
            if (bp <= x) {
                ans = max(ans,bp);
                break;
            }
        }
    }
    cout << ans << endl;
}