155
It was a war that Japan assumed would be ended in " 3 to 6 months "; at the time of Pearl Harbor , it had been going on for 5 years , at the cost of over half a million Japanese lives .
 Japan: attacker
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:
 Japan: attacker