# Write a function to find maximum of three numbers.
def max_of_three(num1, num2, num3):
    if (num1 >= num2) and (num1 >= num3):
        lnum = num1
    elif (num2 >= num1) and (num2 >= num3):
        lnum = num2
    else:
        lnum = num3
    return lnum
