#!/usr/bin/python3.8
def add(x,y):
	return x+y
def sub(x+y):
	return x-y
def main():
	while True:
		x=input("Δωσε x¨")
		x=eval(x)
		if x>0: break
	while True:
		y=input("Δωσε y")
		y=eval(y)
		if y<0: break
	a=add(x,y)
	b=sub(x,y)
	print (f'Add={a}')
	print (f'Sub={b}')
if __name__=="__main__":
	main()