##### Short Problem Definition:

Compute number of integers divisible by k in range [a..b].

##### Link

##### Complexity:

expected worst-case time complexity is `O(1)`

expected worst-case space complexity is `O(1)`

##### Execution:

This little check required a bit of experimentation. One needs to start from the first valid value that is bigger than A and a multiply of K.

##### Solution:

```
def solution(A, B, K):
if B < A or K <= 0:
raise Exception("Invalid Input")
min_value = ((A + K -1) // K) * K
if min_value > B:
return 0
return ((B - min_value) // K) + 1
```