Solved AOJ 0094, 0095, 0267, 0520, 0577, 1054, 1085, 1159, 1510, 2100, 2150, 2152, 2188 and 2219 and ksnctf 002, 008, 020 and 025 and Land of Lisp Chap.2 and Chap.5 and POJ 1244 and 1522 and TOJ 1601 and 1925.