RK and his partition method

RK was playing with Strings. One day he came across the following problem. He wanted to find the number of ways to split a string 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 very large, print it modulo 109 + 7. Input - The only line of the input consist of a string