P10170 [DTCPC 2024] Xiao Fang and Xiao Cube.

Xiao Fang does not want to become Xiao Cube.

You are given a string consisting of lowercase letters. Find how many intervals $[l,r]$ satisfy that the substring represented by this interval is a palindrome, and the number of occurrences of each character does not exceed $2$.

One line contains a string $S$ ($\lvert S\rvert\leq 5\times 10^4$).

One line contains one number, which is the answer.

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