Books and Friends

Rishi wants to collect some books. He wants to buy the **maximum** possible number of books so that he can study. Now, you have to help him by selecting the shops from the given $N$ book shops (The selected shops should be continuous). There are $N$ continuous shops (from $1$ to $N$) and the $i^{th}$ shop is having an integer $A[i]$. - If $A[i]$ is positive, he can buy $A[i]$ number of books