require 'bigdecimal'                                                                
                                                                                    
def how_many_times(i, k)                                                            
  result = 0                                                                        
  i2 = i                                                                            
  while i2 <= k do                                                                  
    result += 1                                                                     
    i2 *= 2                                                                         
  end                                                                               
  result                                                                            
end                                                                                 
                                                                                    
FAKE = '1'                                                                          
                                                                                    
A = gets.split.map(&:to_i)                                                          
N = A[0]                                                                            
K = A[1]                                                                            
                                                                                    
total_pred = BigDecimal('0.0')                                                      
if N < K                                                                            
  (1..N).each do |i|                                                                
    h = how_many_times(i, K)                                                        
    total_pred += BigDecimal("#{0.5**h}") * BigDecimal(FAKE) / BigDecimal("#{N}")    
  end                                                                               
else                                                                                
  (1...K).each do |i|                                                               
    h = how_many_times(i, K)                                                        
    add = BigDecimal("#{0.5**h}") * BigDecimal(FAKE) / BigDecimal("#{N}")           
    total_pred += add                                                               
  end                                                                               
                                                                                    
  add = BigDecimal(FAKE) * BigDecimal("#{(N - K + 1)}") / BigDecimal("#{N}")        
  total_pred += add                                                                 
end                                                                                 
                                                                                    
puts (total_pred / BigDecimal(FAKE)).to_s('F')    