1683
But most of the vulnerabilities he found were actually in new code written specifically for Tizen within the last two years .
 ( discover vulnerability: found,  Tizen: vulnerable system, the last two years: time, he: discoverer, most of the vulnerabilities: vulnerability) 
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:
 ( discover vulnerability: found,  Tizen: vulnerable system, the last two years: time, he: discoverer, most of the vulnerabilities: vulnerability) 