JOIN

 Problem Statement

### Problem Statement

You have the number s. You may change this number. In each step you can apply one of two possible changes:

• Multiply your current number by b.
Your goal is to change s into t using the minimal number of steps.

You are given the longs s, t, a, and b. Compute and return the smallest number of steps in which we can turn s into t, or -1 if changing s into t is not possible.

### Definition

 Class: MultiplyAddPuzzle Method: minimalSteps Parameters: long, long, long, long Returns: long Method signature: long minimalSteps(long s, long t, long a, long b) (be sure your method is public)

### Constraints

-s will be between 0 and 1,000,000,000,000,000,000 (10^18), inclusive.
-t will be between 0 and 1,000,000,000,000,000,000 (10^18), inclusive.
-a will be between 0 and 1,000,000,000,000,000,000 (10^18), inclusive.
-b will be between 0 and 1,000,000,000,000,000,000 (10^18), inclusive.

### Examples

0)

 `10` `40` `4` `2`
`Returns: 2`
 At the beginning you have the number 10. In each step you can either add 4 to your number, or you can multiply it by 2. You want to reach the number 40. The optimal solution is to use multiplication twice, changing 10 to 10*2 = 20 and then changing 20 to 20*2 = 40.
1)

 `10` `28` `4` `2`
`Returns: 2`
 The same setting, but now the goal is the number t = 28. Again, it is possible to reach this number in two steps. In the first step we add 4, going from 10 to 10+4 = 14. In the second step we multiply by 2, going from 14 to 14*2 = 28.
2)

 `10` `99` `4` `2`
`Returns: -1`
 Whatever you do, the number you'll have will always be even, so it's impossible to reach the odd number 99.
3)

 `345` `12345` `1` `10`
`Returns: 895`
4)

 `1000000000000000000` `1000000000000000000` `1000000000000000000` `1000000000000000000`
`Returns: 0`

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This problem was used for:
Single Round Match 707 Sponsored By Blizzard Round 1 - Division I, Level Two