9402: ABC207 —— B - Hydrate
[Creator : ]
Description
There is a container with $A$ cyan balls. Takahashi will do the following operation as many times as he likes (possibly zero times):
- add $B$ cyan balls and $C$ red balls into the container.
Takahashi's objective is to reach a situation where the number of cyan balls in the container is at most $D$ times the number of red balls in it.
Determine whether the objective is achievable. If it is achievable, find the minimum number of operations needed to achieve it.
- add $B$ cyan balls and $C$ red balls into the container.
Takahashi's ob
Determine whether the ob
Input
Input is given from Standard Input in the following format:
```
$A$ $B$ $C$ $D$
```
```
$A$ $B$ $C$ $D$
```
Output
If Takahashi's objective is achievable, print the minimum number of operations needed to achieve it. Otherwise, print `-1`.
Constraints
### Constraints
- $1 \leq A,B,C,D \leq 10^5$
- All values in input are integers.
- $1 \leq A,B,C,D \leq 10^5$
- All values in input are integers.
Sample 1 Input
5 2 3 2
Sample 1 Output
2
Before the first operation, the container has 5 cyan balls and 0 red balls. Since 5 is greater than 0 multiplied by D=2, Takahashi's objective is not yet achieved.
Just after the first operation, the container has 7 cyan balls and 3 red balls. Since 7 is greater than 3 multiplied by 2, the objective is still not achieved.
Just after the second operation, the container has 9 cyan balls and 6 red balls. Since 9 is not greater than 6 multiplied by 2, the objective is achieved.
Thus, the answer is 2.
Just after the first operation, the container has 7 cyan balls and 3 red balls. Since 7 is greater than 3 multiplied by 2, the ob
Just after the second operation, the container has 9 cyan balls and 6 red balls. Since 9 is not greater than 6 multiplied by 2, the ob
Thus, the answer is 2.
Sample 2 Input
6 9 2 3
Sample 2 Output
-1
No matter how many times Takahashi repeats the operation, his objective will never be achieved.