AT_abc449_c [ABC449C] Comfortable Distance

You are given a string $ S $ of length $ N $ consisting of lowercase English letters. Find the number of pairs of integers $ (i, j) $ satisfying all of the following conditions: - $ 1 \leq i \leq j \leq N $ - $ S_i = S_j $ - $ L \leq j - i \leq R $

The input is given from Standard Input in the following format: > $ N $ $ L $ $ R $ $ S $

Output the answer.

### Sample Explanation 1 The pairs of integers satisfying all the conditions in the problem statement are $ (i, j) = (2, 6), (3, 5) $ , for a total of two pairs. ### Constraints - $ 2 \leq N \leq 5 \times 10^5 $ - $ 1 \leq L \leq R \leq N - 1 $ - $ N, L, R $ are integers. - $ S $ is a string of length $ N $ consisting of lowercase English letters.