Question: What upper middle income country under East Asia & Pacific region which covers the topic about Social Protection & Labor: Migration
? Indicate the short name of the said country.
SQL: SELECT DISTINCT T1.ShortName FROM Country AS T1 INNER JOIN footnotes AS T2 ON T1.CountryCode = T2.CountryCode INNER JOIN Series AS T3 ON T2.Seriescode = T3.SeriesCode WHERE T1.IncomeGroup = 'Upper middle income' AND T1.Region = 'East Asia & Pacific' AND T3.Topic = 'Social Protection & Labor: Migration'