Declension table of ?yatprathama

Masculine	Singular	Dual	Plural
Nominative	yatprathamaḥ	yatprathamau	yatprathamāḥ
Vocative	yatprathama	yatprathamau	yatprathamāḥ
Accusative	yatprathamam	yatprathamau	yatprathamān
Instrumental	yatprathamena	yatprathamābhyām	yatprathamaiḥ yatprathamebhiḥ
Dative	yatprathamāya	yatprathamābhyām	yatprathamebhyaḥ
Ablative	yatprathamāt	yatprathamābhyām	yatprathamebhyaḥ
Genitive	yatprathamasya	yatprathamayoḥ	yatprathamānām
Locative	yatprathame	yatprathamayoḥ	yatprathameṣu

Compound yatprathama -

Adverb -yatprathamam -yatprathamāt