Please answer a question about the following article about New York City:

Over 600,000 students are enrolled in New York City's over 120 higher education institutions, the highest number of any city in the United States, including over half million in the City University of New York (CUNY) system alone in 2014. In 2005, three out of five Manhattan residents were college graduates, and one out of four had a postgraduate degree, forming one of the highest concentrations of highly educated people in any American city. New York City is home to such notable private universities as Barnard College, Columbia University, Cooper Union, Fordham University, New York University, New York Institute of Technology, Pace University, and Yeshiva University. The public CUNY system is one of the largest universities in the nation, comprising 24 institutions across all five boroughs: senior colleges, community colleges, and other graduate/professional schools. The public State University of New York (SUNY) system also serves New York City, as well as the rest of the state. The city also has other smaller private colleges and universities, including many religious and special-purpose institutions, such as St. John's University, The Juilliard School, Manhattan College, The College of Mount Saint Vincent, The New School, Pratt Institute, The School of Visual Arts, The King's College, and Wagner College.

The City University of New York system consists of how many institutions?
24