import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    int l = sc.nextInt();

    BigDecimal a = new BigDecimal(l).divide(new BigDecimal(3), 6, RoundingMode.DOWN);
    BigDecimal w = a;
    BigDecimal h = a;
    BigDecimal d = a;

    BigDecimal cube = w.multiply(h).multiply(d);

    BigDecimal rect;
    BigDecimal oldRect = cube;
    while (true) {
      w = w.subtract(BigDecimal.valueOf(0.1));
      h = h.add(BigDecimal.valueOf(0.1));
      rect = w.multiply(h).multiply(d);
      if (cube.compareTo(rect) > 0) {
        System.out.println(oldRect.doubleValue());
        return;
      }
      oldRect = rect;
    }
  }
} import java.math.BigDecimal; BigDecimal java.math import java.math.RoundingMode; RoundingMode java.math import java.util.Scanner; Scanner java.util public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    int l = sc.nextInt();

    BigDecimal a = new BigDecimal(l).divide(new BigDecimal(3), 6, RoundingMode.DOWN);
    BigDecimal w = a;
    BigDecimal h = a;
    BigDecimal d = a;

    BigDecimal cube = w.multiply(h).multiply(d);

    BigDecimal rect;
    BigDecimal oldRect = cube;
    while (true) {
      w = w.subtract(BigDecimal.valueOf(0.1));
      h = h.add(BigDecimal.valueOf(0.1));
      rect = w.multiply(h).multiply(d);
      if (cube.compareTo(rect) > 0) {
        System.out.println(oldRect.doubleValue());
        return;
      }
      oldRect = rect;
    }
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    int l = sc.nextInt();

    BigDecimal a = new BigDecimal(l).divide(new BigDecimal(3), 6, RoundingMode.DOWN);
    BigDecimal w = a;
    BigDecimal h = a;
    BigDecimal d = a;

    BigDecimal cube = w.multiply(h).multiply(d);

    BigDecimal rect;
    BigDecimal oldRect = cube;
    while (true) {
      w = w.subtract(BigDecimal.valueOf(0.1));
      h = h.add(BigDecimal.valueOf(0.1));
      rect = w.multiply(h).multiply(d);
      if (cube.compareTo(rect) > 0) {
        System.out.println(oldRect.doubleValue());
        return;
      }
      oldRect = rect;
    }
  } main {
    Scanner sc = new Scanner(System.in);

    int l = sc.nextInt();

    BigDecimal a = new BigDecimal(l).divide(new BigDecimal(3), 6, RoundingMode.DOWN);
    BigDecimal w = a;
    BigDecimal h = a;
    BigDecimal d = a;

    BigDecimal cube = w.multiply(h).multiply(d);

    BigDecimal rect;
    BigDecimal oldRect = cube;
    while (true) {
      w = w.subtract(BigDecimal.valueOf(0.1));
      h = h.add(BigDecimal.valueOf(0.1));
      rect = w.multiply(h).multiply(d);
      if (cube.compareTo(rect) > 0) {
        System.out.println(oldRect.doubleValue());
        return;
      }
      oldRect = rect;
    }
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int l = sc.nextInt(); l sc.nextInt() sc.nextInt sc BigDecimal a = new BigDecimal(l).divide(new BigDecimal(3), 6, RoundingMode.DOWN); a new BigDecimal(l).divide(new BigDecimal(3), 6, RoundingMode.DOWN) new BigDecimal(l).divide new BigDecimal(l) new BigDecimal(3) 6 RoundingMode.DOWN RoundingMode RoundingMode.DOWN BigDecimal w = a; w a BigDecimal h = a; h a BigDecimal d = a; d a BigDecimal cube = w.multiply(h).multiply(d); cube w.multiply(h).multiply(d) w.multiply(h).multiply w.multiply(h) w.multiply w h d BigDecimal rect; rect BigDecimal oldRect = cube; oldRect cube while (true) {
      w = w.subtract(BigDecimal.valueOf(0.1));
      h = h.add(BigDecimal.valueOf(0.1));
      rect = w.multiply(h).multiply(d);
      if (cube.compareTo(rect) > 0) {
        System.out.println(oldRect.doubleValue());
        return;
      }
      oldRect = rect;
    } true {
      w = w.subtract(BigDecimal.valueOf(0.1));
      h = h.add(BigDecimal.valueOf(0.1));
      rect = w.multiply(h).multiply(d);
      if (cube.compareTo(rect) > 0) {
        System.out.println(oldRect.doubleValue());
        return;
      }
      oldRect = rect;
    } w = w.subtract(BigDecimal.valueOf(0.1)) w w.subtract(BigDecimal.valueOf(0.1)) w.subtract w BigDecimal.valueOf(0.1) BigDecimal.valueOf BigDecimal 0.1 h = h.add(BigDecimal.valueOf(0.1)) h h.add(BigDecimal.valueOf(0.1)) h.add h BigDecimal.valueOf(0.1) BigDecimal.valueOf BigDecimal 0.1 rect = w.multiply(h).multiply(d) rect w.multiply(h).multiply(d) w.multiply(h).multiply w.multiply(h) w.multiply w h d if (cube.compareTo(rect) > 0) {
        System.out.println(oldRect.doubleValue());
        return;
      } cube.compareTo(rect) > 0 cube.compareTo(rect) cube.compareTo cube rect 0 {
        System.out.println(oldRect.doubleValue());
        return;
      } System.out.println(oldRect.doubleValue()) System.out.println System.out System System.out oldRect.doubleValue() oldRect.doubleValue oldRect return; oldRect = rect oldRect rect String[] args args public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    int l = sc.nextInt();

    BigDecimal a = new BigDecimal(l).divide(new BigDecimal(3), 6, RoundingMode.DOWN);
    BigDecimal w = a;
    BigDecimal h = a;
    BigDecimal d = a;

    BigDecimal cube = w.multiply(h).multiply(d);

    BigDecimal rect;
    BigDecimal oldRect = cube;
    while (true) {
      w = w.subtract(BigDecimal.valueOf(0.1));
      h = h.add(BigDecimal.valueOf(0.1));
      rect = w.multiply(h).multiply(d);
      if (cube.compareTo(rect) > 0) {
        System.out.println(oldRect.doubleValue());
        return;
      }
      oldRect = rect;
    }
  }
} public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    int l = sc.nextInt();

    BigDecimal a = new BigDecimal(l).divide(new BigDecimal(3), 6, RoundingMode.DOWN);
    BigDecimal w = a;
    BigDecimal h = a;
    BigDecimal d = a;

    BigDecimal cube = w.multiply(h).multiply(d);

    BigDecimal rect;
    BigDecimal oldRect = cube;
    while (true) {
      w = w.subtract(BigDecimal.valueOf(0.1));
      h = h.add(BigDecimal.valueOf(0.1));
      rect = w.multiply(h).multiply(d);
      if (cube.compareTo(rect) > 0) {
        System.out.println(oldRect.doubleValue());
        return;
      }
      oldRect = rect;
    }
  }
} Main
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);

    int l = sc.nextInt();

    BigDecimal a = new BigDecimal(l).divide(new BigDecimal(3), 6, RoundingMode.DOWN);
    BigDecimal w = a;
    BigDecimal h = a;
    BigDecimal d = a;

    BigDecimal cube = w.multiply(h).multiply(d);

    BigDecimal rect;
    BigDecimal oldRect = cube;
    while (true) {
      w = w.subtract(BigDecimal.valueOf(0.1));
      h = h.add(BigDecimal.valueOf(0.1));
      rect = w.multiply(h).multiply(d);
      if (cube.compareTo(rect) > 0) {
        System.out.println(oldRect.doubleValue());
        return;
      }
      oldRect = rect;
    }
  }
}