Create a combat function that takes the player's current health and the amount of damage recieved, and returns the player's new health.
Health can't be less than 0.
def combat(health, damage):
    ret=health-damage
    if 0>ret:
        ret=0
    return ret
def combat(health, damage):
    ret=health-damage
    if 0>ret:
        ret=0
    return ret