P9761 [ROIR 2021] Two Machines (Day 1)

**Translated from [ROIR 2021](http://neerc.ifmo.ru/school/archive/2020-2021.html) Day 1 T1 [ Два станка](http://neerc.ifmo.ru/school/archive/2020-2021/ru-olymp-regional-2021-day1.pdf)**。

There are two machines. The first machine needs $a$ minutes to start up, and then it produces $x$ parts per minute. The second machine needs $b$ minutes to start up, and then it produces $y$ parts per minute. The two machines cannot be in the startup process at the same time. You have a total of $k$ minutes. Find the maximum number of parts that can be produced.

The first line contains an integer $k$. The second line contains two integers $a, x$. The third line contains two integers $b, y$.

Output a single integer: the maximum number of parts that can be produced.

[Sample Explanation]: If you start the second machine first and then start the first machine, you can produce $3\times 15+5\times 4=65$ parts. [Constraints]: For all subtasks, $0\le k,a,x,b,y\le 10^9$. The final answer can be stored in `long long`. | Subtask ID | Special Constraints | Score | | :-: | :-: | :-: | | $1$ | $a=x=0$ | $17$ | | $2$ | $a=b=0$ | $14$ | | $3$ | $a=b$ | $20$ | | $4$ | $x=y$ | $20$ | | $5$ | None | $29$ | Translated by ChatGPT 5