a = 10
b = 5
c = a + b
print('--------------------------')
a = 10
b = 12
c = a + b
a += 5  # todo a=10 + a=5 =15
print(a)
print('--------------------------')
money = 1000
money = money - 50
money = money - 20
print(money)
print('--------------------------')
money = 1000
money -= 50
money -= 20
print(money)
