suma = 0
a = float(input())
while a != 0:
if a > 0: suma = suma + a
else: suma = suma
a = float(input())
print(suma)
c3VtYSA9IDAKYSA9IGZsb2F0KGlucHV0KCkpCndoaWxlIGEgIT0gMDoKCWlmIGEgPiAwOiBzdW1hID0gc3VtYSArIGEKCWVsc2U6IHN1bWEgPSBzdW1hIAoJYSA9IGZsb2F0KGlucHV0KCkpCnByaW50KHN1bWEp