Problem: Given a string s, find the number of ways to split s to substrings such that if there are k substrings (p1, p2, p3, ..., pk) in partition, then pi = pk - i + 1 for all i (1 ≤ i ≤ k) and k is even.

Since the number of ways can be large, print it modulo 109 + 7.

Input

The only line of input contains a string s (2 ≤ |s| ≤ 106) of even length consisting of lowercase Latin letters. 

Output

Print one integer, the number of ways of partitioning the string modulo 109 + 7.

Examples

Input

abcdcdab


Output

1

Input

abbababababbab


Output

3

Note

In the first case, the only way to partition the string is ab|cd|cd|ab.

In the second case, the string can be partitioned as ab|b|ab|ab|ab|ab|b|ab or ab|b|abab|abab|b|ab or abbab|ab|ab|abbab.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
inline int read() {
  int w = 1, s = 0;
  char ch = getchar();
  while (!isdigit(ch)) {
    if (ch == '-') w = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    s = s * 10 + ch - '0';
    ch = getchar();
  }
  return w * s;
}
int n, diff[2010100], cnt, fail[2010100], len[2001010], Slink[2001010],
    pos[1010010], las, ch[1010010][26], g[2000100], f[2000100];
char s[1010000], tmp[1001010];
inline int pls(int a, int b) {
  a += b;
  return a >= mod ? a - mod : a;
}
inline void Insert(int c, int idx) {
  int p = las;
  while (tmp[idx] != tmp[idx - len[p] - 1]) p = fail[p];
  if (!ch[p][c]) {
    int np = ++cnt, k = fail[p];
    len[np] = len[p] + 2;
    while (tmp[idx] != tmp[idx - len[k] - 1]) k = fail[k];
    fail[np] = ch[k][c];
    ch[p][c] = np;
    diff[np] = len[np] - len[fail[np]];
    Slink[np] = (diff[np] == diff[fail[np]]) ? Slink[fail[np]] : fail[np];
  }
  las = ch[p][c];
  pos[idx] = las;
}
int main() {
  scanf("%s", s + 1);
  n = strlen(s + 1);
  int cur = 0;
  for (register int i = 1; i <= n; i += 2) tmp[i] = s[++cur];
  cur = n + 1;
  for (register int i = 2; i <= n; i += 2) tmp[i] = s[--cur];
  fail[0] = 1;
  len[1] = -1;
  cnt = 1;
  for (register int i = 1; i <= n; ++i) Insert(tmp[i] - 'a', i);
  f[0] = 1;
  for (register int i = 1; i <= n; ++i) {
    for (register int p = pos[i]; p; p = Slink[p]) {
      g[p] = f[i - (len[Slink[p]] + diff[p])];
      g[p] = pls(g[p], diff[p] == diff[fail[p]] ? g[fail[p]] : 0);
      if ((i & 1)) continue;
      f[i] = pls(g[p], f[i]);
    }
  }
  cout << f[n];
  return 0;
}