The Tyrell corporation uses a state-of-the-art electronic document system
that controls all aspects of document creation, viewing, editing, and
distribution. Document security is handled via access control
lists (ACLs). An ACL defines a set of entities that have access to the
document, and for each entity defines the set of rights that it has.
Entities are denoted by uppercase letters; an entity might be a single
individual or an entire division. Rights are denoted by lowercase letters;
examples of rights are a for append, d for
delete, e for edit, and r for read.

The ACL for a document is stored along with that document, but there is
also a separate ACL log stored on a separate log server. All
documents start with an empty ACL, which grants no rights to anyone. Every
time the ACL for a document is changed, a new entry is written to the log.
An entry is of the form ExR, where E is a nonempty set of
entities, R is a nonempty set of rights, and x is either "+",
"–", or "=". Entry E+R says to grant all the rights
in R to all the entities in E, entry
E–R says to remove all the rights in R from
all the entities in E, and entry E=R says that all the
entities in E have exactly the rights in R and no others. An
entry might be redundant in the sense that it grants an entity a right it
already has and/or denies an entity a right that it doesn't have. A log is
simply a list of entries separated by commas, ordered chronologically from
oldest to most recent. Entries are cumulative, with newer entries taking
precedence over older entries if there is a conflict.

Periodically the Tyrell corporation will run a security check by using
the logs to compute the current ACL for each document and then comparing it
with the ACL actually stored with the document. A mismatch indicates a
security breach. Your job is to write a program that, given an ACL log,
computes the current ACL.