Amusing Numbers

Description

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 QN,K. For example, Q11,2 = 4. Given numbers K and M find the smallest N such that QN,K = M.
Input

Input contains two integer numbers K and M (1 <= K, M <= 109) separated by a space.
Output

If such N that QN,K = M exists then write to the output the smallest such N, otherwise write 0.
Sample Input

100000001 1000000000
Sample Output

100000000888888879