Radix (25)

输入描述:

Each input file contains one test case. Each case occupies a line which contains 4 positive integers:
N1 N2 tag radix
Here N1 and N2 each has no more than 10 digits.  A digit is less than its radix and is chosen from the set {0-9, a-z} where 0-9 represent the decimal numbers 0-9, and a-z represent the decimal numbers 10-35.  The last number "radix" is the radix of N1 if "tag" is 1, or of N2 if "tag" is 2.

输出描述:

For each test case, print in one line the radix of the other number so that the equation N1 = N2 is true.  If the equation is impossible, print "Impossible".  If the solution is not unique, output the smallest possible radix.

6 110 1 10

2<br/>Sample Input 2:<br/>1 ab 1 2<br/>Sample Output 2:<br/>Impossible