
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        //99999は門番
        int[] check = {1,4,8,9,16,25,27,32,36,49,64,81,100,121,125,128,144,169,196,216,225,243,256,289,324,343,361,400,441,484,512,529,576,625,676,729,784,841,900,961,1000,99999};

        Scanner sc = new Scanner(System.in);
        int max  = sc.nextInt();

        for (int i = 0; i < check.length; i++) {
            if(max < check[i]){
                System.out.println(check[i - 1]);
                return;
            }
        }
    }

}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz