import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int[] num = {1, 4, 8, 16, 32, 64, 128, 256, 512,  9, 27, 81, 243, 729,  16, 64, 256, 1024, 25, 125, 625,  36, 216,  49, 343,  64, 512,  81, 729,  100, 1000, 121,  144,  169,  196,  225,  256,  289,  324,  361,  400, 441, 484,  529,  576,  625,  676,  729,  784,  841, 900,  961};
        Arrays.sort(num);
        int X = sc.nextInt();
        int max = -1;
        for(int i = num.length; i > 0; i--){
            int n = num[i - 1];
            if(n <= X){
                max = Math.max(max, n);
                break;
            }
        }
        System.out.println(max);
    }
} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int[] num = {1, 4, 8, 16, 32, 64, 128, 256, 512,  9, 27, 81, 243, 729,  16, 64, 256, 1024, 25, 125, 625,  36, 216,  49, 343,  64, 512,  81, 729,  100, 1000, 121,  144,  169,  196,  225,  256,  289,  324,  361,  400, 441, 484,  529,  576,  625,  676,  729,  784,  841, 900,  961};
        Arrays.sort(num);
        int X = sc.nextInt();
        int max = -1;
        for(int i = num.length; i > 0; i--){
            int n = num[i - 1];
            if(n <= X){
                max = Math.max(max, n);
                break;
            }
        }
        System.out.println(max);
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int[] num = {1, 4, 8, 16, 32, 64, 128, 256, 512,  9, 27, 81, 243, 729,  16, 64, 256, 1024, 25, 125, 625,  36, 216,  49, 343,  64, 512,  81, 729,  100, 1000, 121,  144,  169,  196,  225,  256,  289,  324,  361,  400, 441, 484,  529,  576,  625,  676,  729,  784,  841, 900,  961};
        Arrays.sort(num);
        int X = sc.nextInt();
        int max = -1;
        for(int i = num.length; i > 0; i--){
            int n = num[i - 1];
            if(n <= X){
                max = Math.max(max, n);
                break;
            }
        }
        System.out.println(max);
    } main {
        Scanner sc = new Scanner(System.in);
        int[] num = {1, 4, 8, 16, 32, 64, 128, 256, 512,  9, 27, 81, 243, 729,  16, 64, 256, 1024, 25, 125, 625,  36, 216,  49, 343,  64, 512,  81, 729,  100, 1000, 121,  144,  169,  196,  225,  256,  289,  324,  361,  400, 441, 484,  529,  576,  625,  676,  729,  784,  841, 900,  961};
        Arrays.sort(num);
        int X = sc.nextInt();
        int max = -1;
        for(int i = num.length; i > 0; i--){
            int n = num[i - 1];
            if(n <= X){
                max = Math.max(max, n);
                break;
            }
        }
        System.out.println(max);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int[] num = {1, 4, 8, 16, 32, 64, 128, 256, 512,  9, 27, 81, 243, 729,  16, 64, 256, 1024, 25, 125, 625,  36, 216,  49, 343,  64, 512,  81, 729,  100, 1000, 121,  144,  169,  196,  225,  256,  289,  324,  361,  400, 441, 484,  529,  576,  625,  676,  729,  784,  841, 900,  961}; num {1, 4, 8, 16, 32, 64, 128, 256, 512,  9, 27, 81, 243, 729,  16, 64, 256, 1024, 25, 125, 625,  36, 216,  49, 343,  64, 512,  81, 729,  100, 1000, 121,  144,  169,  196,  225,  256,  289,  324,  361,  400, 441, 484,  529,  576,  625,  676,  729,  784,  841, 900,  961} 1 4 8 16 32 64 128 256 512 9 27 81 243 729 16 64 256 1024 25 125 625 36 216 49 343 64 512 81 729 100 1000 121 144 169 196 225 256 289 324 361 400 441 484 529 576 625 676 729 784 841 900 961 Arrays.sort(num) Arrays.sort Arrays num int X = sc.nextInt(); X sc.nextInt() sc.nextInt sc int max = -1; max -1 1 for(int i = num.length; i > 0; i--){
            int n = num[i - 1];
            if(n <= X){
                max = Math.max(max, n);
                break;
            }
        } int i = num.length; int i = num.length; i num.length num num.length i > 0 i 0 i-- i-- i {
            int n = num[i - 1];
            if(n <= X){
                max = Math.max(max, n);
                break;
            }
        } {
            int n = num[i - 1];
            if(n <= X){
                max = Math.max(max, n);
                break;
            }
        } int n = num[i - 1]; n num[i - 1] num i - 1 i 1 if(n <= X){
                max = Math.max(max, n);
                break;
            } n <= X n X {
                max = Math.max(max, n);
                break;
            } max = Math.max(max, n) max Math.max(max, n) Math.max Math max n break; System.out.println(max) System.out.println System.out System System.out max String[] args args public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int[] num = {1, 4, 8, 16, 32, 64, 128, 256, 512,  9, 27, 81, 243, 729,  16, 64, 256, 1024, 25, 125, 625,  36, 216,  49, 343,  64, 512,  81, 729,  100, 1000, 121,  144,  169,  196,  225,  256,  289,  324,  361,  400, 441, 484,  529,  576,  625,  676,  729,  784,  841, 900,  961};
        Arrays.sort(num);
        int X = sc.nextInt();
        int max = -1;
        for(int i = num.length; i > 0; i--){
            int n = num[i - 1];
            if(n <= X){
                max = Math.max(max, n);
                break;
            }
        }
        System.out.println(max);
    }
} public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int[] num = {1, 4, 8, 16, 32, 64, 128, 256, 512,  9, 27, 81, 243, 729,  16, 64, 256, 1024, 25, 125, 625,  36, 216,  49, 343,  64, 512,  81, 729,  100, 1000, 121,  144,  169,  196,  225,  256,  289,  324,  361,  400, 441, 484,  529,  576,  625,  676,  729,  784,  841, 900,  961};
        Arrays.sort(num);
        int X = sc.nextInt();
        int max = -1;
        for(int i = num.length; i > 0; i--){
            int n = num[i - 1];
            if(n <= X){
                max = Math.max(max, n);
                break;
            }
        }
        System.out.println(max);
    }
} Main
import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int[] num = {1, 4, 8, 16, 32, 64, 128, 256, 512,  9, 27, 81, 243, 729,  16, 64, 256, 1024, 25, 125, 625,  36, 216,  49, 343,  64, 512,  81, 729,  100, 1000, 121,  144,  169,  196,  225,  256,  289,  324,  361,  400, 441, 484,  529,  576,  625,  676,  729,  784,  841, 900,  961};
        Arrays.sort(num);
        int X = sc.nextInt();
        int max = -1;
        for(int i = num.length; i > 0; i--){
            int n = num[i - 1];
            if(n <= X){
                max = Math.max(max, n);
                break;
            }
        }
        System.out.println(max);
    }
}
