解が37通りもある問題ねぇ…

(みかんの個数,りんごの個数,レモンの個数,梨の個数)=
(0,0,12,12)(0,5,8,12)(0,10,4,12)(0,15,0,12)(1,3,9,12) (1,8,5,12)(1,13,1,12)(2,1,10,12)(2,6,6,12)(2,11,2,12)
(3,4,7,12)(3,9,3,12)(4,2,8,12)(4,7,4,12)(4,12,0,12) (5,0,9,12)(5,5,5,12)(5,10,1,12)(6,3,6,12)(6,8,2,12)
(7,1,7,12)(7,6,3,12)(8,4,4,12)(8,9,0,12)(9,2,5,12) (9,7,1,12)(10,0,6,12)(10,5,2,12)(11,3,3,12)(12,1,4,12)
(12,6,0,12)(13,4,1,12)(14,2,2,12)(15,0,3,12)(16,3,0,12) (17,1,1,12)(20,0,0,12)