def probability_of_collision(car_1, car_2):
    """
    Calculate the probablity of a collision based on the car turns
    Args:
        car_1 (string): The turning direction of car_1
        car_2 (string): The turning direction of car_2
        
    Returns:
        float: the probability of a collision
    """
    
    probability = 0.0 # you should change this value based on the directions.
    
    
    if car_1 == "L":
        # Case Car1 L and Car2 L
        if car_2 == "L":
            probability = 0.5
        # Case Car1 L and Car2 S    
        elif car_2 == "S":
            probability = 0.25
        # Case Car1 L and Car2 R (this is all other possible cases)
        else:
            probability = 0.1
        
    elif car_1 == "S":
        # Case Car1 S and Car2 L
        if car_2 == "L":
            probability = 0.25
        # Case Car1 S and Car2 S
        elif car_2 == "S":
            probability = 0.02
        # Case Car1 S and Car2 R (this is all other possible cases)
        else:
            probability = 0.1
        
    else: # Car1 R
        # Case Car1 R and Car2 L
        if car_2 == "L":
            probability = 0.1
        # Case Car1 R and Car2 S
        elif car_2 == "S":
            probability = 0.1
        # Case Car1 R and Car2 R (this is all other possible cases)
        else:
            probability = 0.01
        
    
    return probability
    
def test():
    num_correct = 0
    
    p1 = probability_of_collision("L", "L")
    if p1 == 0.5:
        num_correct += 1
    
    p2 = probability_of_collision("L", "R")
    if p2 == 0.1:
        num_correct += 1
    
    p3 = probability_of_collision("L", "S")
    if p3 == 0.25:
        num_correct += 1
    
    p4 = probability_of_collision("S", "R")
    if p4 == 0.1:
        num_correct += 1
    
    print("You got", num_correct, "out of 4 correct")
    
test()