AMATH - Another Mathematical Problem

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Given two numbers n (1<=n<10100) and k (1<=k<=100), you are to determine whether there exists a positive integer T which satisfies that for every positive integer a, na+T-na is divisible by 10k.

Input

Multiple test cases. Each test case contains two space-separated integers n and k. Input terminate by EOF.

The number of test cases will not more than 20.

Output

For each test case, you should output the smallest positive integer number T which satisfies the condition above, or -1 if it doesn't exist.

Example

Input:
32 2

Output:
4


Added by:Fudan University Problem Setters
Date:2007-07-01
Time limit:1s
Source limit:2048B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: C99 ERL JS-RHINO
Resource:Folklore, description and standard program by Blue Mary