Author:  A. Baranov  Time limit:  1 sec  
Input file:  Standard input  Memory limit:  512 Mb  
Output file:  Standard output 
Consider a set of all possible strings of exactly n characters, consisting of digits and small Latin letters.
Hamming distance H(A, B) is equal to the number of positions i from 1 to n
where A[i] ≠ B[i].
Let us define P(A, B) as a set of strings of length n equidistant from A and B
({ C: H(A, C) = H(B, C)}).
Determine the number of strings in the set P(A, B).
Since the answer may be too large, output the remainder of it divided by 10^{9}.
Input contains two strings: A и B.
Output a single integer — the answer.
1 ≤ n ≤ 10^{4}.
No.  Standard input  Standard output 

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