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: Accepted)

#include <bits/stdc++.h>
#include <string>
#include <algorithm>
#include <string.h>
using namespace std;
 
int main(){
    
    int X,max=1,tmp;
    cin >> X;

    for(int i=1;i<=100;i++){
        tmp=i;
        for(int j=1;j<=100;j++){
            tmp=tmp*i;
            if(tmp>max&&tmp<=X){
            max=tmp;
            }
            if(tmp>X)break;
        }
    }

    cout << max <<endl;

    return 0;
}