Trailhead Beacon Segment Sum

A trail ranger's handheld monitor keeps a single running log while a hiker moves along a ridge trail. Every time the hiker passes one of the numbered beacon posts staked along the trail, the monitor writes a 0 into the log to mark that moment. In between two consecutive beacon markers, the monitor instead writes one entry for every elevation-gain reading it picks up along that stretch of trail. The log always starts and ends with a beacon marker, and it is guaranteed that at least one elevation-gain reading was recorded between any two consecutive beacon markers.

To build a clean trip report, collapse every stretch between two consecutive beacon markers into a single number: the sum of all elevation-gain readings recorded during that stretch. The beacon markers themselves carry no elevation information and must not appear in the report.

Input format

• Line 1: a single integer n, the number of entries in the log.
• Line 2: n space-separated integers a_1 ... a_n, the log in the order it was recorded.

Output format

Print the collapsed stretch totals, in the order the stretches occurred, separated by single spaces, on one line.

Constraints

• 3 <= n <= 2*10^5
• a_1 = a_n = 0
• 0 <= a_i <= 1000 for every i
• every entry equal to 0 is a beacon marker; every other entry is a strictly positive elevation-gain reading (1 to 1000)
• between any two consecutive beacon markers there is at least one elevation-gain reading

8
0 3 1 0 4 5 2 0

4 11

5
0 9 0 3 0

9 3