The invention concerns a compound of the formula (I) wherein Ring A is heterocyclyl; m is 0-4 and each R1 is a group such as hydroxy, halo, trifluoromethyl and cyano; R2 is halo and n is 0-2; and each R4 is a group such as hydroxy, halo, trifluoromethyi and cyano; p is (M; and R3 is amino or hydroxy; or pharmaceutically-acceptaWe salts or in-vivo-hydrolysable ester or amide thereof processes for their preparation, pharmaceutical compositions containing them and their use in the treatment of diseases or medical condions mediated by histone deacetylase.