{"raw_statement":[{"iden":"background","content":"小方不想变成小立方。"},{"iden":"statement","content":"给你一个由小写字母组成的字符串，求有多少个区间 $[l,r]$，满足这个区间所表示的串是回文的，且每个字符的出现次数不超过 $2$。"},{"iden":"input","content":"一行一个字符串 $S$（$\\lvert S\\rvert\\leq 5\\times 10^4$）。"},{"iden":"output","content":"一行一个数，表示答案。"}],"translated_statement":null,"sample_group":[["ababa","8"]],"show_order":[],"formal_statement":null,"simple_statement":null,"has_page_source":false}