To an aqueous solution containing ions such as  $A{l}^{+3},Z{n}^{2+},C{a}^{2+},F{e}^{3+},N{i}^{2+},B{a}^{2+}andC{u}^{2+}$ was added conc HCl followed by  $H_{2}S$ . The total number of cations precipitated during this reaction are_____