P8015 [COCI 2013/2014 #4] GUMA

Given a rectangle with $N + 1$ columns, the $i$-th column must be evenly divided into $A_i$ parts by making $A_i - 1$ horizontal cuts. Find the minimum number of cuts needed to finish the partition as required. $Tips:$ In one cut, you may cut in one or more columns that are not necessarily consecutive.

The first line contains a positive integer $N$, indicating that the rectangle has $N + 1$ columns. The next $N + 1$ lines each contain a positive integer $A_i$, indicating that the $i$-th column must be evenly divided into $A_i$ parts by making $A_i - 1$ horizontal cuts.

One line containing a positive integer, indicating the minimum number of cuts.

**[Sample Explanation #3]**  A total of $7$ cuts. **[Constraints]** For $20\%$ of the testdata, $1 \le N \le 100$. For $100\%$ of the testdata, $1 \le N, A_i \le 10^5$. **[Source]** The score of this problem is set according to the original COCI problem, with a full score of $120$. Translated from [COCI2013-2014 CONTEST #4](https://hsin.hr/coci/archive/2013_2014/contest4_tasks.pdf) _**T4 GUMA**_. Translated by ChatGPT 5