program windy;
    var
      n,i,m,k,j,n1,n2:longint;
      c:boolean;
    begin
      readln(m,n,k);
      c:=true;
      i:=k+1;
      while c and (i<=10000) do
        begin
          n1:=0;
          n2:=0;
          for j:=2 to trunc(sqrt(i)) do
            begin
              if i mod j=0 then n1:=n1+1;
              if (i-k) mod j=0 then n2:=n2+1;
            end;
          if (n1+1=n) and (n2+1=m) then c:=false
            else i:=i+1;
         end;
       if c then writeln(0);
       if not c then writeln(i)
     end.