C-M-u runs the command backward-up-list (found in global-map), which
is an interactive compiled Lisp function in `lisp.el'.
It is bound to <C-M-up>, C-M-u, ESC <C-up>.
(backward-up-list &optional ARG ESCAPE-STRINGS NO-SYNTAX-CROSSING)
Move backward out of one level of parentheses.
This command will also work on other parentheses-like expressions
defined by the current language mode