The present invention provides a novel P2X3 and/or P2X2/3 receptor antagonist.A compound represented by the formula (I): wherein Z1 is optionally protected hydroxy, etc.; Z2 is —C(═O)—, etc.; Z3a and Z3b are taken together ═O or ═S; t is an integer of 0 to 4; R4a and R4b are each independently, hydrogen or substituted or unsubstituted lower alkyl, etc.; m and n are each independently an integer of 0 to 2; k is an integer of 0 or 1; Ring A is an aromatic carbocyclic ring or a heterocyclic ring, etc.; B is aromatic carbocyclic ring-diyl or heterocyclic ring-diyl, etc.; R1a and R1b are each independently halogen, hydroxy, substituted or unsubstituted lower alkyl, etc.; R2 is substituted or unsubstituted alkyl, etc.; R3 is substituted or unsubstituted alkyl, substituted or unsubstituted aryl or a substituted or unsubstituted heterocyclic group, etc.; or its pharmaceutically acceptable salt, or a solvate thereof is provided.