### Database Schema:
CREATE TABLE cites (
	cited_paper_id	TEXT	NOT NULL	PRIMARY KEY,
	citing_paper_id	TEXT	NOT NULL	PRIMARY KEY
);

CREATE TABLE content (
	paper_id	TEXT	NOT NULL	PRIMARY KEY,
	word_cited_id	TEXT	NOT NULL	PRIMARY KEY,
	foreign key (paper_id) references paper (paper_id)
);

CREATE TABLE paper (
	paper_id	TEXT	NOT NULL	PRIMARY KEY,
	class_label	TEXT	NOT NULL
);

### User's Query:
What is the most cited word? How many papers was that word cited in?

### Extra Knowledge:
most cited word refers to max(count(word_cited_id);
SELECT word_cited_id, COUNT(paper_id) FROM content GROUP BY word_cited_id ORDER BY COUNT(word_cited_id) DESC LIMIT 1