import sys sys.setrecursionlimit(10**7) from functools import lru_cache mod = 10 ** 9 + 7 @lru_cache(maxsize=None) def f(start, goal): val = 1 ind = 1 while start + ind <= goal - ind: if R.get(start, start + ind) == R.get(goal - ind, goal): val += f(start + ind, goal - ind) val %= mod ind += 1 return val class RollingHash(): def __init__(self, s): self._mod = 2 ** 64 - 1 self._base = 4649 n = len(s) self.h = [0] * (n + 1) self.pw = [1] * (n + 1) for i in range(n): self.h[i + 1] = self.h[i] * self._base + ord(s[i]) self.h[i + 1] %= self._mod for i in range(n): self.pw[i + 1] = self.pw[i] * self._base self.pw[i + 1] %= self._mod """ s[l:r]のhash値 """ def get(self, l, r): return (self.h[r] - self.h[l] * self.pw[r - l]) % self._mod S = input() R = RollingHash(S) print(f(0, len(S)))