#P1177B. Digits Sequence (Hard Edition)
Digits Sequence (Hard Edition)
Description
Let's write all the positive integer numbers one after another from $1$ without any delimiters (i.e. as a single string). It will be the infinite sequence starting with 123456789101112131415161718192021222324252627282930313233343536...
Your task is to print the $k$-th digit of this sequence.
The first and only line contains integer $k$ ($1 \le k \le 10^{12}$) — the position to process ($1$-based index).
Print the $k$-th digit of the resulting infinite sequence.
Input
The first and only line contains integer $k$ ($1 \le k \le 10^{12}$) — the position to process ($1$-based index).
Output
Print the $k$-th digit of the resulting infinite sequence.
Samples
7
7
21
5