import datetime
import random
my_string = ""
score = 0
lives = 3

while True:
    random_letters = ["a","b","c","d","e","f","g","h","i","j"]
    my_string = my_string + random.choice(random_letters)

    start_time = datetime.datetime.now() # Get initial time
    print("Please enter",my_string)
    my_input=input(":")
    finish_time = datetime.datetime.now()    #Get finish time
    reaction_time = finish_time - start_time # difference in time

    if my_input == my_string:
        print("\nIt took you:",reaction_time)
        score = score + 10
    else:
        if lives < 1:
            print("Bad luck you failed")
            break #end the loop
        else:
            lives = lives -1
        print("You have",lives)
print("Game over",score)