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>
const int maxn = 1e6 + 7;
const long long mod = 1e9 + 7;
using namespace std;
char str[maxn], s[maxn];
int n, cnt;
long long f[maxn], g[maxn];
struct node {
  int fail, len, last, delta;
  int son[26];
} t[maxn];
void build() {
  cnt = 1;
  t[0].fail = 1;
  t[0].len = 0;
  t[1].fail = 0;
  t[1].len = -1;
  int now = 1;
  for (int i = 1; i <= n; i++) {
    while (s[i] != s[i - t[now].len - 1]) now = t[now].fail;
    if (!t[now].son[s[i] - 'a']) {
      cnt++;
      int k = t[now].fail;
      while (s[i] != s[i - t[k].len - 1]) k = t[k].fail;
      t[cnt].fail = t[k].son[s[i] - 'a'];
      t[now].son[s[i] - 'a'] = cnt;
      t[cnt].len = t[now].len + 2;
      t[cnt].delta = t[cnt].len - t[t[cnt].fail].len;
      if (t[cnt].delta == t[t[cnt].fail].delta)
        t[cnt].last = t[t[cnt].fail].last;
      else
        t[cnt].last = cnt;
    }
    now = t[now].son[s[i] - 'a'];
    for (int j = now; j > 0; j = t[t[j].last].fail) {
      g[j] = f[i - t[t[j].last].len];
      if (t[j].last != j) g[j] = (g[j] + g[t[j].fail]) % mod;
      if (i % 2 == 0) f[i] = (f[i] + g[j]) % mod;
    }
  }
}
int main() {
  scanf("%s", str);
  n = strlen(str);
  int num = 0;
  for (int i = 1; i <= n; i += 2) s[i] = str[num++];
  num = n - 1;
  for (int i = 2; i <= n; i += 2) s[i] = str[num--];
  f[0] = 1;
  build();
  printf("%lld", f[n]);
}