2477
However , after Yahoo disclosed the breach , a few months later , the company learned of an even bigger hack that involved 1 billion Yahoo user accounts and further rocked the company 's reputation .
 ( data breach: an even bigger hack,  Yahoo user accounts: compromised data, 1 billion: number of data, the company: victim, a few months later: time) 
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:
 ( data breach: an even bigger hack,  Yahoo user accounts: compromised data, 1 billion: number of data, the company: victim, a few months later: time) 