# Author: Sandeep Belgavi. Synthetic exercise; no network or provider calls.
allowed={"researcher","reviewer"}
seen=set()
remaining=3
def handoff(task,agent):
    global remaining
    key=(task,agent)
    if agent not in allowed or key in seen or remaining==0:return "STOP"
    seen.add(key);remaining-=1
    return "ACCEPT"
assert handoff("t1","researcher")=="ACCEPT"
assert handoff("t1","reviewer")=="ACCEPT"
assert handoff("t1","researcher")=="STOP"
assert handoff("t1","payment_writer")=="STOP"
print("two handoffs accepted; loop and unknown role stopped")