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11/09/2024 17:33:02

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# Занятие 6

## A. Amusing Numbers

Ограничения: время – 2s/4s, память – 32MiB Ввод: input.txt или стандартный ввод Вывод: output.txt или стандартный вывод
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Let us consider the set of integer numbers between 1 and N inclusive. Let us order them lexicographically (i. e. like in the vocabulary), for example, for N = 11 the order would be: 1, 10, 11, 2, 3, 4, 5, 6, 7, 8, 9.
Let us denote the position of the number K in this ordering as Q_{N,K}. For example, Q_{11,2}\ =\ 4. Given numbers K and M find the smallest N such that Q_{N,K}\ =\ M.
Input
Input file contains two integer numbers K and M (1\ ≤\ K,\ M\ ≤\ 10^9) separated by a space.
Output
If such N that Q_{N,K}\ =\ M exists then write to the output file the smallest such N, otherwise write 0.

Input #1

2 4


Output #1

11


Input #2

2 1


Output #2

0


Input #3

100000001 1000000000


Output #3

100000000888888879


Input #4

1000000000 11


Output #4

0

Source: 2002-2003 ACM Northeastern European Regional Programming Contest