The Aggregate of Feeling
There are three kinds of feeling: pleasant feeling, painful feeling, & neither-pleasant-nor-painful feeling... Whatever is experienced physically or mentally as pleasant & gratifying is pleasant feeling. Whatever is experienced physically or mentally as painful & hurting is painful feeling. Whatever is experienced physically or mentally as neither gratifying nor hurting is neither-pleasant-nor-painful feeling... Pleasant feeling is pleasant in remaining and painful in changing. Painful feeling is painful in remaining and pleasant in changing. Neither-pleasant-nor-painful feeling is pleasant when conjoined with knowledge and painful when devoid of knowledge.
Tisso kho imā āvuso visākha vedanā: sukhā vedanā, dukkhā vedanā, adukkhamasukhā vedanāti.
Yaṃ kho āvuso visākha kāyikaṃ vā cetasikaṃ vā sukhaṃ sātaṃ vedayitaṃ, ayaṃ sukhā vedanā. Yaṃ kho āvuso visākha kāyikaṃ vā cetasikaṃ vā dukkhaṃ asātaṃ vedayitaṃ, ayaṃ dukkhā vedanā. Yaṃ kho āvuso visākha kāyikaṃ vā cetasikaṃ vā nevasātaṃ nāsātaṃ vedayitaṃ, ayaṃ adukkhamasukhā vedanāti.
Sukhā kho āvuso visākha vedanā ṭhitisukhā vipariṇāmadukkhā, dukkhā vedanā ṭhitidukkhā vipariṇāmasukhā, adukkhamasukhā vedanā ñāṇasukhā aññāṇadukkhāti.
MN 44 Culavedalla Sutta: The Shorter Set of Questions-and-Answers
Tisso = three
imā (nom. pl.) = these
vedanā (nom. pl.) = feelings
sukhā = pleasant
dukkhā = painful
adukkhamasukhā = neither pleasant nor painful
kāyikaṃ vā cetasikaṃ vā = physically or mentaly
sukhaṃ sātaṃ vedayitaṃ = experienced as pleasant and gratifying
ayaṃ (nom. sg.) = this
ṭhiti-sukhā = pleasant in remaining
vipariṇāma-dukkhā = unpleasant in changing
ñāṇa-sukhā = pleasant when there is knowledge
aññāṇa-dukkhā = painful when there isn't knowledge