Derived Column Transformation with a proper SSIS expression

Hi, I have one column coming from a source.

1. This column (columnX) has 3456//fgtrhfnbjjb/tyutj.

I need the new column (ColumnX) between "//" and "/" which is "fgtrhfnbjjb". I use derived column in SSIS. and get trouble to proceed.

2. I have another column (columnY) has .../gygfdyfg,   /.../gycgvycgvy,

I need the new column has:   3456//gygfdyfg, 3456//gycgvycgvy