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 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 the smallest such N, otherwise write 0.
Samples
input  output 

2 4
 11

2 1
 0

100000001 1000000000
 100000000888888879

1000000000 11
 0

Problem Author: Andrew Stankevich
Problem Source: 20022003 ACM Northeastern European Regional Programming Contest