The Infinite Digit String

Difficulty: 1400 2000 ms 128 MB

math

All positive integers are written in a row: 123456789101112131415... Print the K-th digit (1-indexed).

Input: one integer K.

Output: the K-th digit of the infinite string.

Constraints:

• 1 ≤ K ≤ 10¹⁸

Sample Tests

11

0

3

3

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