Database: world_development_indicators
Question: What is the series code for number of infant deaths in year 1965 for the country whose full name is Islamic State of Afghanistan?
SQL: SELECT DISTINCT T3.Seriescode FROM Country AS T1 INNER JOIN Indicators AS T2 ON T1.CountryCode = T2.CountryCode INNER JOIN CountryNotes AS T3 ON T2.CountryCode = T3.Countrycode WHERE T2.IndicatorName = 'Number of infant deaths' AND T1.LongName = 'Islamic State of Afghanistan' AND T2.Year = 1965