CF1065A.Vasya and Chocolate

There is a special offer in Vasya's favourite supermarket: if the customer buys $a$ chocolate bars, he or she may take $b$ additional bars for free. This special offer can be used any number of times.

Vasya currently has $s$ roubles, and he wants to get as many chocolate bars for free. Each chocolate bar costs $c$ roubles. Help Vasya to calculate the maximum possible number of chocolate bars he can get!

瓦西娅最喜爱的超市有一个特别优惠：如果顾客购买 $a$ 块巧克力，就可以免费再拿 $b$ 块。该优惠可以使用任意多次。

瓦西娅目前有 $s$ 卢布，他希望尽可能多地免费获得巧克力。每块巧克力售价为 $c$ 卢布。请帮助瓦西娅计算他最多能获得多少块巧克力！

The first line contains one integer $t$ ($1 \le t \le 100$) — the number of testcases.

Each of the next $t$ lines contains four integers $s, a, b, c~(1 \le s, a, b, c \le 10^9)$ — the number of roubles Vasya has, the number of chocolate bars you have to buy to use the special offer, the number of bars you get for free, and the cost of one bar, respectively.

第一行包含一个整数 $t$（$1 \le t \le 100$）—— 测试用例的数量。

接下来的 $t$ 行中，每行包含四个整数 $s, a, b, c$（$1 \le s, a, b, c \le 10^9$）—— 分别表示瓦夏拥有的卢布数、使用特价优惠所需购买的巧克力条数、免费获得的巧克力条数，以及每条巧克力的价格。

Print $t$ lines. $i$-th line should contain the maximum possible number of chocolate bars Vasya can get in $i$-th test.

输出 $t$ 行。第 $i$ 行应包含 Vasya 在第 $i$ 个测试中能获得的巧克力棒的最大可能数量。

In the first test of the example Vasya can buy $9$ bars, get $3$ for free, buy another bar, and so he will get $13$ bars.

In the second test Vasya buys $1000000000$ bars and gets $1000000000000000000$ for free. So he has $1000000001000000000$ bars.

在示例的第一个测试中，瓦西娅可以购买 $9$ 块巧克力，免费获得 $3$ 块，再额外购买 $1$ 块，因此他总共获得 $13$ 块巧克力。

在第二个测试中，瓦西娅购买了 $1000000000$ 块巧克力，并免费获得 $1000000000000000000$ 块。因此他总共拥有 $1000000001000000000$ 块巧克力。