816
North Korea ' s military may have fired a laser at a U . S . helicopter in March , a U . S . official said Tuesday , as the communist state ditched its last legal obligation to keep itself free of nuclear weapons .
 military: attacker; helicopter: target; laser: instrument
Given event type and trigger, please tell me the arguments of all the listed option. Output format is "name1: role1; name2: role2". 
Event type: attack 
  Option: victim, attacker, place, target, instrument 
Text: {0} 
Answer:
 military: attacker; helicopter: target; laser: instrument