From Wiktionary, the free dictionary
листу́ • (listú) m inan
- dative singular of лист (list)
листу́ • (lystú) m inan
- dative singular of лист (lyst): letter, sheet, leaf
ли́сту • (lýstu) m inan sg
- genitive/dative/locative singular of лист (lyst): leaves (uncountable)