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<algorithm>
#include<string>
#include<cstring>
#include<cmath>
using namespace std;
/*
int pow(int x,int y)
{
    int sum=0;
    for(int i=2;i<=y;i++){
        x*=x;
    }
    sum=x;
    return sum;
}*/
int main()
{
    int n;
    cin>>n;
    int t=1;
    int sum=0;
    int sum_max=0;
    for(int i=1;i<=10;i++){
        sum=0;
        for(int j=2;j<=10;j++){
            sum=pow(i,j);
            if(sum>n){
                break;
            }
            else sum_max=max(sum_max,sum);
        }
    }
    cout<<sum_max<<endl;
    return 0;
}