import java.io.IOException;
import java.io.InputStream;
import java.util.*;
import java.math.BigDecimal;
 
public class Main {
	
    public static void main(String[] args) {
    	FastScanner sc = new FastScanner();
 
    	int n = sc.nextInt();
    	int k = sc.nextInt();
    	
    	BigDecimal sum = BigDecimal.valueOf(0);
    	
    	for(int i=1; i<=n; i++){
    		if(i>=k){
    			sum = sum.add(BigDecimal.valueOf((double)1/(double)n));
    		}
    		else{
    			double need = (double)k / (double)i;
        		double x = Math.log(need) / Math.log(2);
        		int y = (int) Math.ceil(x);
        		sum = sum.add(iterationPow(BigDecimal.valueOf((double)1/(double)n),BigDecimal.valueOf(0.5),y));
        		
    		}
    	}
    
    	System.out.println(sum);
    }
    
	static BigDecimal iterationPow(BigDecimal moto,BigDecimal x, long n){
	    BigDecimal sum = moto;
	    while(n>0){
	        if((n&1)== 1){  //ビットが立っていたら
	            sum = sum.multiply(x);
	        }
	        x = x.multiply(x);
	        n >>= 1;
	    }
	    return sum;
	}
	
}
 
 
class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
    private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
    public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() { return Double.parseDouble(next());}
}
/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