#[allow(unused_imports)] use std::cmp::{max, min, Ordering}; #[allow(unused_imports)] use std::collections::{HashMap, HashSet, BinaryHeap, VecDeque, BTreeSet, BTreeMap}; #[allow(unused_imports)] use std::iter::FromIterator; #[allow(unused_imports)] use std::io::stdin; 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 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(unused_macros)] macro_rules! get { ($t:ty) => { { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.trim().parse::<$t>().unwrap() } }; ($($t:ty),*) => { { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); let mut iter = line.split_whitespace(); ( $(iter.next().unwrap().parse::<$t>().unwrap(),)* ) } }; ($t:ty; $n:expr) => { (0..$n).map(|_| get!($t) ).collect::>() }; ($($t:ty),*; $n:expr) => { (0..$n).map(|_| get!($($t),*) ).collect::>() }; ($t:ty ;;) => { { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.split_whitespace() .map(|t| t.parse::<$t>().unwrap()) .collect::>() } }; } #[allow(unused_macros)] macro_rules! debug { ($($a:expr),*) => { println!(concat!($(stringify!($a), " = {:?}, "),*), $($a),*); } } const M: usize = 1000000007; fn rec(s: &[char], i: usize, memo: &mut [Option]) -> usize { if let Some(res) = memo[i] { return res; } let mut sum = 1; for k in 1.. { if i + k > s.len() - i - k { break; } if s[i..i + k] == s[s.len() - i - k..s.len() - i] { sum += rec(s, i + k, memo); sum %= M; } } memo[i] = Some(sum); sum } fn main() { let s: Vec = util::line().chars().collect(); let mut memo = vec![None; s.len()]; println!("{}", rec(&s, 0, &mut memo)); // debug!(memo); }