instruction: what is the number of patients whose ethnicity is hispanic/latino - puerto rican and diagnoses long title is acute on chronic combined systolic and diastolic heart failure?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id WHERE demographic.ethnicity = "HISPANIC/LATINO - PUERTO RICAN" AND diagnoses.long_title = "Acute on chronic combined systolic and diastolic heart failure"