1470
Leeds Teaching Hospitals NHS Trust reported four ransomware attacks in 2016 , and University Hospitals Bristol NHS Foundation Trust and Kings College Hospital NHS Foundation Trust sustained three ransomware attacks each last year .
 ( ransom: ransomware attacks,  2016: time, Leeds Teaching Hospitals NHS Trust: victim) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: phishing, data breach, ransom, discover vulnerability, patch vulnerability, Arguments type: vulnerable system, capabilities, vulnerability, number of victim, issues addressed, compromised data, damage amount, common vulnerabilities and exposures, victim, patch number, number of data, tool, discoverer, time, purpose, place, payment method, releaser, vulnerable system version, attacker, supported platform, patch, price, vulnerable system owner, trusted entity, attack pattern. 
Text: {0} 
Answer:
 ( ransom: ransomware attacks,  2016: time, Leeds Teaching Hospitals NHS Trust: victim) 