Both Greece and its lenders said on Tuesday they were optimistic they could broker a deal within days on a multi-billion euro bailout, striking a surprisingly upbeat tone on a process previously fraught with bitterness. A bailout worth up to 86 billion euros ($94.5 billion) must be settled by Aug. 20 — or a second bridge loan agreed — if Greece is to pay off debt of 3.5 billion euros to the European Central Bank that matures on that day. Wrapping up a day of talks in Athens, Greek Finance Minister Euclid Tsakalotos said negotiations were going better than expected.