13809번 - Champernowne Constant 다국어

Champernown constant is an irrational number represented in decimal by “0.” followed by concatenation of all positive integers in the increasing order. The first few digits of this constant are: 0.123456789101112 .. .

Your task is to write a program that outputs the K digits of Chapnernown constant starting at the N-th place for given two natural numbers K and N.

The input has multiple lines. Each line has two positive integers N and K (N ≤ 10⁹ , K ≤ 100) separated by a space.

The end of input is indicated by a line with two zeros. This line should not be processed.

For each line, output a line that contains the K digits.