Question: harmony of the seas는 언제부터 항해를 시작했나요
Answer: 2019-12-29; 2019 12 29; 12/29/2019; 12 29 2019; 12-29-2019; 29 12월 2019; 2019 12월 29; 2019-12-29; 29 12 2019; 2019 december, 29; 29-12-2019; 29/12/2019