import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.InputMismatchException;

public class Main {
	static InputStream is;
	static PrintWriter out;
	static String INPUT = "";
	
	static void solve()
	{
		int n = ni();
		if(n == 0){
			out.println(4);
		}else{
			out.printf("%.20f\n", Math.pow(3, n)/Math.pow(4, n-1));
		}
//		FB[] a = new FB[101];
//		a[0] = new FB(4);
//		a[1] = new FB(3);
//		for(int i = 2;i <= 100;i++){
//			a[i] = new FB(19).mul(a[i-1]).sub(new FB(12).mul(a[i-2])).div(new FB(4));
//			tr(i, a[i]);
//		}
	}
	
	public static class FB implements Comparable<FB> {
		public BigInteger num, den;
		
		public FB(){ this.num = BigInteger.ZERO; this.den = BigInteger.ONE; }
		public FB(long num) { this.num = BigInteger.valueOf(num); this.den = BigInteger.ONE; }
		public FB(long num, long den) { this.num = BigInteger.valueOf(num); this.den = BigInteger.valueOf(den); reduce(); }
		public FB(BigInteger num) {	this.num = num; this.den = BigInteger.ONE;}
		public FB(BigInteger num, BigInteger den) {	this.num = num;	this.den = den;	reduce();}
		
		public FB reduce()
		{
			if(den.signum() == 0) {
			}else if(num.signum() == 0) {
				den = BigInteger.ONE;
			}else {
				if(den.signum() < 0) {
					num = num.negate();
					den = den.negate();
				}
				BigInteger g = num.gcd(den);
				num = num.divide(g);
				den = den.divide(g);
			}
			return this;
		}
		
		public static FB add(FB a, FB b){ return new FB(a.num.multiply(b.den).add(a.den.multiply(b.num)), a.den.multiply(b.den)); }
		public static FB sub(FB a, FB b){ return new FB(a.num.multiply(b.den).subtract(a.den.multiply(b.num)), a.den.multiply(b.den)); }
		public static FB mul(FB a, FB b){ return new FB(a.num.multiply(b.num), a.den.multiply(b.den)); }
		public static FB div(FB a, FB b){ return new FB(a.num.multiply(b.den), a.den.multiply(b.num)); }
		public static FB inv(FB a) { return new FB(a.den, a.num); }
		
		public FB add(FB b){ num = num.multiply(b.den).add(den.multiply(b.num)); den = den.multiply(b.den); return reduce(); }
		public FB sub(FB b){ num = num.multiply(b.den).subtract(den.multiply(b.num)); den = den.multiply(b.den); return reduce(); }
		public FB mul(FB b){ num = num.multiply(b.num); den = den.multiply(b.den); return reduce(); }
		public FB div(FB b){ num = num.multiply(b.den); den = den.multiply(b.num); return reduce(); }
		public FB inv() { BigInteger d = num; num = den; den = d; return reduce(); }
		
		public String toString() { return num.toString() + "/" + den.toString(); }
		public String toStringSimple() { return den.equals(BigInteger.ONE) ? num.toString() : num.toString() + "/" + den.toString(); }
		
		public int compareTo(FB f) { return num.multiply(f.den).compareTo(f.num.multiply(den)); }
		
		public boolean simpleEquals(FB f) {	return num.equals(f.num) && den.equals(f.den); }

		public boolean equals(Object o)
		{
			if(o == null)return false;
			FB f = (FB) o;
			return num.multiply(f.den).equals(f.num.multiply(den));
		}
	}
	
	public static void main(String[] args) throws Exception
	{
		long S = System.currentTimeMillis();
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		solve();
		out.flush();
		long G = System.currentTimeMillis();
		tr(G-S+"ms");
	}
	
	private static boolean eof()
	{
		if(lenbuf == -1)return true;
		int lptr = ptrbuf;
		while(lptr < lenbuf)if(!isSpaceChar(inbuf[lptr++]))return false;
		
		try {
			is.mark(1000);
			while(true){
				int b = is.read();
				if(b == -1){
					is.reset();
					return true;
				}else if(!isSpaceChar(b)){
					is.reset();
					return false;
				}
			}
		} catch (IOException e) {
			return true;
		}
	}
	
	private static byte[] inbuf = new byte[1024];
	static int lenbuf = 0, ptrbuf = 0;
	
	private static int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private static boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private static int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private static double nd() { return Double.parseDouble(ns()); }
	private static char nc() { return (char)skip(); }
	
	private static String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private static char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private static char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private static int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private static int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}