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The hackers warned that they will delete all files on infected systems if no payment is received within seven days .
 ( ransom: payment,  seven days: time, The hackers: attacker, delete all files on infected systems: attack pattern) 
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: payment,  seven days: time, The hackers: attacker, delete all files on infected systems: attack pattern) 