I have installed **urxvt** and **mc**.  

There is a combination `Alt` + `S` in urxvt and the same combination in mc.  

When i use mc through urxvt and press `Alt` + `S`, command of the urxvt works instead of command of the mc.  

How can i disable shortcut `Alt` + `S` in urxvt in order to use this combination in mc?