
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

 class Main{

	static class FastReader {
		BufferedReader br;
		StringTokenizer st;

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
	}

	static boolean prime[] = new boolean[1001];

	public static void main(String[] args) {
		FastReader sc = new FastReader();
		stones(sc);
		/*
		 * String str =sc.nextLine(); int q=sc.nextInt(); while(q-->0){ int
		 * len=sc.nextInt(); int[] ch=new int[26]; boolean chk=false; for(int
		 * i=0;i<str.length()-len+1;i++){ String sub=str.substring(i, i+len);
		 * System.out.println(sub); boolean p=method(sub); if(p){ chk=true; //
		 * break; } } System.out.println(chk?len:-1);
		 */
	}

	private static void stones(FastReader sc) {
		int x = sc.nextInt(),ans=0;
		int[] aa = { 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 };
		for(int i=0;i<aa.length;i++){
			if(aa[i]<=x){
				ans=aa[i];
			} else{
				break;
			}
		}
		System.out.println(ans);
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util class Main{

	static class FastReader {
		BufferedReader br;
		StringTokenizer st;

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
	}

	static boolean prime[] = new boolean[1001];

	public static void main(String[] args) {
		FastReader sc = new FastReader();
		stones(sc);
		/*
		 * String str =sc.nextLine(); int q=sc.nextInt(); while(q-->0){ int
		 * len=sc.nextInt(); int[] ch=new int[26]; boolean chk=false; for(int
		 * i=0;i<str.length()-len+1;i++){ String sub=str.substring(i, i+len);
		 * System.out.println(sub); boolean p=method(sub); if(p){ chk=true; //
		 * break; } } System.out.println(chk?len:-1);
		 */
	}

	private static void stones(FastReader sc) {
		int x = sc.nextInt(),ans=0;
		int[] aa = { 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 };
		for(int i=0;i<aa.length;i++){
			if(aa[i]<=x){
				ans=aa[i];
			} else{
				break;
			}
		}
		System.out.println(ans);
	}
} Main static boolean prime[] = new boolean[1001]; prime new boolean[1001] 1001 public static void main(String[] args) {
		FastReader sc = new FastReader();
		stones(sc);
		/*
		 * String str =sc.nextLine(); int q=sc.nextInt(); while(q-->0){ int
		 * len=sc.nextInt(); int[] ch=new int[26]; boolean chk=false; for(int
		 * i=0;i<str.length()-len+1;i++){ String sub=str.substring(i, i+len);
		 * System.out.println(sub); boolean p=method(sub); if(p){ chk=true; //
		 * break; } } System.out.println(chk?len:-1);
		 */
	} main {
		FastReader sc = new FastReader();
		stones(sc);
		/*
		 * String str =sc.nextLine(); int q=sc.nextInt(); while(q-->0){ int
		 * len=sc.nextInt(); int[] ch=new int[26]; boolean chk=false; for(int
		 * i=0;i<str.length()-len+1;i++){ String sub=str.substring(i, i+len);
		 * System.out.println(sub); boolean p=method(sub); if(p){ chk=true; //
		 * break; } } System.out.println(chk?len:-1);
		 */
	} FastReader sc = new FastReader(); sc new FastReader() stones(sc) stones sc String[] args args private static void stones(FastReader sc) {
		int x = sc.nextInt(),ans=0;
		int[] aa = { 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 };
		for(int i=0;i<aa.length;i++){
			if(aa[i]<=x){
				ans=aa[i];
			} else{
				break;
			}
		}
		System.out.println(ans);
	} stones {
		int x = sc.nextInt(),ans=0;
		int[] aa = { 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 };
		for(int i=0;i<aa.length;i++){
			if(aa[i]<=x){
				ans=aa[i];
			} else{
				break;
			}
		}
		System.out.println(ans);
	} int x = sc.nextInt() x sc.nextInt() sc.nextInt sc ans=0; ans 0 int[] aa = { 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 }; aa { 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 } 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 for(int i=0;i<aa.length;i++){
			if(aa[i]<=x){
				ans=aa[i];
			} else{
				break;
			}
		} int i=0; int i=0; i 0 i<aa.length i aa.length aa aa.length i++ i++ i {
			if(aa[i]<=x){
				ans=aa[i];
			} else{
				break;
			}
		} {
			if(aa[i]<=x){
				ans=aa[i];
			} else{
				break;
			}
		} if(aa[i]<=x){
				ans=aa[i];
			} else{
				break;
			} aa[i]<=x aa[i] aa i x {
				ans=aa[i];
			} ans=aa[i] ans aa[i] aa i {
				break;
			} break; System.out.println(ans) System.out.println System.out System System.out ans FastReader sc sc static class FastReader {
		BufferedReader br;
		StringTokenizer st;

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
	} FastReader BufferedReader br; br StringTokenizer st; st public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		} FastReader {
			br = new BufferedReader(new InputStreamReader(System.in));
		} br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		} next {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		} while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			} st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			} try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				} IOException e {
					e.printStackTrace();
				} e.printStackTrace() e.printStackTrace e {
					st = new StringTokenizer(br.readLine());
				} st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
			return Integer.parseInt(next());
		} nextInt {
			return Integer.parseInt(next());
		} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() {
			return Long.parseLong(next());
		} nextLong {
			return Long.parseLong(next());
		} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble() {
			return Double.parseDouble(next());
		} nextDouble {
			return Double.parseDouble(next());
		} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		} nextLine {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		} String str = ""; str "" try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			} catch (IOException e) {
				e.printStackTrace();
			} IOException e {
				e.printStackTrace();
			} e.printStackTrace() e.printStackTrace e {
				str = br.readLine();
			} str = br.readLine() str br.readLine() br.readLine br return str; str

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

 class Main{

	static class FastReader {
		BufferedReader br;
		StringTokenizer st;

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
	}

	static boolean prime[] = new boolean[1001];

	public static void main(String[] args) {
		FastReader sc = new FastReader();
		stones(sc);
		/*
		 * String str =sc.nextLine(); int q=sc.nextInt(); while(q-->0){ int
		 * len=sc.nextInt(); int[] ch=new int[26]; boolean chk=false; for(int
		 * i=0;i<str.length()-len+1;i++){ String sub=str.substring(i, i+len);
		 * System.out.println(sub); boolean p=method(sub); if(p){ chk=true; //
		 * break; } } System.out.println(chk?len:-1);
		 */
	}

	private static void stones(FastReader sc) {
		int x = sc.nextInt(),ans=0;
		int[] aa = { 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 };
		for(int i=0;i<aa.length;i++){
			if(aa[i]<=x){
				ans=aa[i];
			} else{
				break;
			}
		}
		System.out.println(ans);
	}
}