Our hero Teemo is attacking an enemy Ashe with poison attacks! When Teemo attacks Ashe, Ashe gets poisoned for a exactly `duration` seconds. More formally, an attack at second `t` will mean Ashe is poisoned during the inclusive time interval `[t, t + duration - 1]`. If Teemo attacks again before the poison effect ends, the timer for it is reset, and the poison effect will end `duration` seconds after the new attack.

You are given a non-decreasing integer array `timeSeries`, where `timeSeries[i]` denotes that Teemo attacks Ashe at second `timeSeries[i]`, and an integer `duration`.

Return the total number of seconds that Ashe is poisoned.

Example 1:

    Input: timeSeries = [1,4], duration = 2
    Output: 4
    Explanation: Teemo's attacks on Ashe go as follows:
    - At second 1, Teemo attacks, and Ashe is poisoned for seconds 1 and 2.
    - At second 4, Teemo attacks, and Ashe is poisoned for seconds 4 and 5.
    Ashe is poisoned for seconds 1, 2, 4, and 5, which is 4 seconds in total.

Example 2:

    Input: timeSeries = [1,2], duration = 2
    Output: 3
    Explanation: Teemo's attacks on Ashe go as follows:
    - At second 1, Teemo attacks, and Ashe is poisoned for seconds 1 and 2.
    - At second 2 however, Teemo attacks again and resets the poison timer. Ashe is poisoned for seconds 2 and 3.
    Ashe is poisoned for seconds 1, 2, and 3, which is 3 seconds in total.

Constraints:

- `1 <= timeSeries.length <= 104`
- `0 <= timeSeries[i], duration <= 107`
- `timeSeries` is sorted in non-decreasing order.