type sir=array[1..200000] of longint;
var f:text;
    i1,i2,j1,j2:byte;
    i,S,n:longint;
     a:sir;
begin
  assign(f,'trei.in'); reset(f);
  readln(f,n); S:=0;
  for i:=1 to n do
        begin
          read(f,a[i]);
          S:=S+a[i] mod 3;
          if a[i] mod 3=1 then
                  begin
                    i1:=i2;
                    i2:=i;
                  end
             else
                if a[i] mod 3=2 then
                    begin
                      j1:=j2;
                      j2:=i;
                    end;
        end;
  close(f); assign(f,'trei.out'); rewrite(f);
  S:=S mod 3;
  case s of
0: write(f,n);
1: if i1<>0 then writeln(f,n-1,chr(10),a[i1])
           else if i2<>0 then writeln(f,n-1,chr(10),a[i2])
                  else writeln(f,n-2,chr(10),a[j1],' ',a[j2]);
2: if j1<>0 then writeln(f,n-1,chr(10),a[j1])
           else if j2<>0 then writeln(f,n-1,chr(10),a[j2])
               else writeln(f,n-2,chr(10),a[i1],' ',a[i2]);
     end;
  close(f);
end.