#[allow(unused_imports)] use std::cmp::{max, min, Ordering}; #[allow(unused_imports)] use std::collections::{HashMap, HashSet, BinaryHeap, VecDeque}; #[allow(unused_imports)] use std::iter::FromIterator; mod util { use std::io::stdin; use std::str::FromStr; use std::fmt::Debug; #[allow(dead_code)] pub fn line() -> String { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.trim().to_string() } #[allow(dead_code)] pub fn get() -> T where ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.trim().parse().unwrap() } #[allow(dead_code)] pub fn gets() -> Vec where ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.split_whitespace() .map(|t| t.parse().unwrap()) .collect() } #[allow(dead_code)] pub fn get2() -> (T, U) where ::Err: Debug, ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); let mut iter = line.split_whitespace(); ( iter.next().unwrap().parse().unwrap(), iter.next().unwrap().parse().unwrap(), ) } #[allow(dead_code)] pub fn get3() -> (S, T, U) where ::Err: Debug, ::Err: Debug, ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); let mut iter = line.split_whitespace(); ( iter.next().unwrap().parse().unwrap(), iter.next().unwrap().parse().unwrap(), iter.next().unwrap().parse().unwrap(), ) } } #[allow(unused_macros)] macro_rules! debug { ($x: expr) => { println!("{}: {:?}", stringify!($x), $x) } } /* struct Manacher<'a, T: 'a + Eq> { s: &'a [T], r: Vec, } impl<'a, T: 'a + Eq> Manacher<'a, T> { fn new(seq: &'a [T]) -> Manacher<'a, T> { let mut r = vec![0; 2 * seq.len() - 1]; let mut i = 0; let mut j = 0; while i < r.len() { while i >= j && i + j < r.len() && Self::get(seq, i - j) == Self::get(seq, i + j) { j += 1; } r[i] = j; let mut k = 1; while i >= k && i + k < r.len() && k + r[i - k] < j { r[i + k] = r[i - k]; k += 1; } i += k; j -= k; } Manacher { s: seq, r: r } } // [l,r] fn is_palindrome(&self, l: usize, r: usize) -> bool { self.r[l + r] >= r - l + 1 } fn get(s: &[T], i: usize) -> Option<&T> { if i & 1 == 1 { None } else { s.get(i) } } } */ fn main() { let s: Vec = util::line().chars().collect(); let s_rev: Vec = s.iter().cloned().rev().collect(); let mut front = Vec::new(); let mut back = Vec::new(); { let mut a = VecDeque::new(); let mut b = VecDeque::new(); for (i, &c) in s.iter().enumerate() { a.push_front(c); b.push_back(c); if a == b { front.push(i); } } } { let mut a = VecDeque::new(); let mut b = VecDeque::new(); for (i, &c) in s.iter().enumerate().rev() { a.push_front(c); b.push_back(c); if a == b { back.push(i); } } } let mut ans = 0; back.sort(); for &p in &front { for (&c, i) in s[p + 1..].iter().zip(1..) { if &s[p + 1..p + 2 + i / 2] == &s_rev[s.len() - p - i - 1..s.len() - p - 1 - (i - 1) / 2] { ans += back.len() as u64 - match back.binary_search(&(p + i as usize + 2)) { Ok(x) => x as u64, Err(x) => x as u64, }; } } } println!("{}", ans); }