solve(ANS,12).
choice([3,14,6,9],ANS),sum(ANS,12)
choice([3,14,6,9],ANS)
ANS=[0,14,6,9]
choice([3,14,6,9],ANS)
ANS=[3,0,0,9]
choice([14,6,9],ANS)
ANS=[0,0,9]
choice([6,9],ANS)
ANS=[0,9]
choice([9],ANS)
choice([],ANS)
ANS=[3,0,0,9]
3+0+0+9=12
単一化に成功
choice([9],ANS)
ANS=[9]
choice([],ANS)
ANS=[]