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;
int ch[1000005][26];
int fail[1000005], len[1000005];
int d[1000005], nxt[1000005];
int tot, last2, now;
void init() {
  tot = last2 = 1;
  len[1] = -1;
  fail[0] = 1;
}
char str[1000005];
int getfail(int x) {
  while (str[now] != str[now - len[x] - 1]) x = fail[x];
  return x;
}
int add(char x) {
  x -= 'a';
  now++;
  int p = getfail(last2);
  if (!ch[p][x]) {
    tot++;
    len[tot] = len[p] + 2;
    fail[tot] = ch[getfail(fail[p])][x];
    d[tot] = len[tot] - len[fail[tot]];
    if (d[tot] == d[fail[tot]])
      nxt[tot] = nxt[fail[tot]];
    else
      nxt[tot] = fail[tot];
    ch[p][x] = tot;
  }
  last2 = ch[p][x];
  return last2;
}
int f[1000005], g[1000005];
char str2[1000005];
int main() {
  scanf("%s", str2 + 1);
  int n = strlen(str2 + 1);
  for (int i = 1; i <= n; i++)
    if (i & 1)
      str[i] = str2[(i + 1) >> 1];
    else
      str[i] = str2[n - (i >> 1) + 1];
  init();
  f[0] = 1;
  for (int i = 1; i <= n; i++) {
    int p = add(str[i]);
    for (; p > 1; p = nxt[p]) {
      g[p] = f[i - len[nxt[p]] - d[p]];
      if (d[p] == d[fail[p]]) g[p] = (g[p] + g[fail[p]]) % 1000000007;
      if (!(i & 1)) f[i] = (f[i] + g[p]) % 1000000007;
    }
  }
  printf("%d\n", f[n]);
  return 0;
}