Nim Game smart and stupid mode

Write a program in which the computer plays against a human opponent. Generate a random integer between 10 and 100 to denote the initial size of the pile. Generate a random integer between 0 and 1 to decide whether the computer or the human takes the first turn.

Generate a random integer between 0 and 1 to decide whether the computer plays smart or stupid . In stupid mode the computer simply takes a random legal value (between 1 and n / 2) from the pile whenever it has a turn. In smart mode the computer takes off enough marbles to make the size of the pile a power of two minus 1—that is, 3, 7, 15, 31, or 63. That is always a legal move, except when the size of the pile is currently one less than a power of two. In that case, the computer makes a random legal move.You will note that the computer cannot be beaten in smart mode when it has the first move, unless the pile size happens to be 15, 31, or 63. Of course, a human player who has the first turn and knows the win ning strategy can win against the computer.

I have no idea how to add a stupid and smart mode. My code so far:

player1=str(input("Enter your name. "))
player2="Computer"
howMany=0
gameover=False
strawsNumber=random.randint(10,20)

if (strawsNumber%4)==1:
    strawsNumber+=1

def removingStrawsComputer():
    removedNumber=random.randint(1,3)
    global strawsNumber
    while removedNumber>strawsNumber:
         removedNumber=random.randint(1,3)
    strawsNumber-=removedNumber #now always remove the straws
    return strawsNumber

def removingStrawsHuman():
    global strawsNumber
    strawsNumber-=howMany
    return strawsNumber

def humanLegalMove():
    global howMany
    legalMove=False
    while not legalMove:
        print("It's your turn, ",player1)
        howMany=int(input("How many straws do you want to remove?(from 1 to 3) "))
        if  howMany>3 or howMany<1:
            print("Enter a number between 1 and 3.")
        else:
            legalMove=True
    while howMany>strawsNumber:
        print("The entered number is greater than a number of straws remained.")
        howMany=int(input("How many straws do you want to remove?"))
    return howMany

def checkWinner(player):
    if strawsNumber==0:
        print(player," wins.")
        global gameover
        gameover=True
        return gameover

def resetGameover():
    global gameover
    gameover=False
    return gameover

def game():
    while gameover==False:
        print("It's ",player2,"turn. The number of straws left: ",removingStrawsComputer())
        checkWinner(player1)
        if gameover==True:
            break
        humanLegalMove()        
        print("The number of straws left: ",removingStrawsHuman())
        checkWinner(player2)

def playAgain():
    answer=input("Do you want to play again?(y/n)")
    resetGameover()
    while answer=="y":
        game()
    else:
        print("Thanks for playing the game")

game()
playAgain()