Which ions are present in each precipitate and which cations are not present in the original solution?

Suppose you have a solution that might contain or all of the following cations: Cu2+, Ag+, Ba2+, and Mn2+. Addition of HCl causes a precipitate to form. After the precipitate is filtered off, H2SO4 is added to the supernate another precipitate forms. This precipitate is filtered off, and a solution of NaOH is added to the supernatant liquid until it is strongly alkaline. No precipitate is formed. Which ions are present in each of the precipitates? Which cations are not present in the original solution?