Digits That Only Fall

Difficulty: 1700 4000 ms 128 MB

digit-dp

Count integers in [L, R] whose digits are non-increasing left to right (like 9741).

Input: one line with two integers L and R.

Output: the count in [L, R].

Constraints:

• 1 ≤ L ≤ R ≤ 10¹⁸

Sample Tests

1 30

15

50 90

31

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