def LostCow(goal):
    flag = False
    tralse = True
    steps = 0
    location = 0
    ptr = 1
    while True:
        #Check wheather to subtract or add
        if tralse:
            #Subtract until we get to correct place to trun around and go the other way
            for i in range(ptr):
                #Add to location (to the right)
                location += 1
                #Increment the steps counter
                steps += 1
                #Check if we've reached the goal yet
                if goal == location:
                    #show the steps
                    return(steps)
                    #Break out
                    flag = True
                    break
        #This is the same thing as above exept for subtracting
        else:
            for i in range(ptr):
                steps += 1
                location -= 1
                if goal == location:
                    return(steps)
                    flag = True
                    break
        if flag == True:
            break
        tralse = not tralse
        ptr *= 2
add = 0
for i in range(1,1001):
    add += LostCow(i)
for i in range(1,1001):
    add += LostCow(0-i)
add /= 200
print(add)