a = 50
b = 20
c = 30
d = 40
print("a-b=", a-b)
print("b+c=", b+c)
print("a*c=", a *c)
print("a/b=", a/b)
print("a+d=", a+d)
print("b/d=", b/d)
print("c*d=", c*d)
print("b-d=",b-d)
YSA9IDUwCmIgPSAyMApjID0gMzAKZCA9IDQwCnByaW50KCJhLWI9IiwgYS1iKQpwcmludCgiYitjPSIsIGIrYykKcHJpbnQoImEqYz0iLCBhICpjKQpwcmludCgiYS9iPSIsIGEvYikKcHJpbnQoImErZD0iLCBhK2QpCnByaW50KCJiL2Q9IiwgYi9kKQpwcmludCgiYypkPSIsIGMqZCkKcHJpbnQoImItZD0iLGItZCk=