CF1041B Buying a TV Set

### 题目大意： 给你$a,b,c,d$，求满足$\frac{x}{y}=\frac{c}{d},x\leq a,y\leq b$的$x,y$的对数

一行$4$个整数$a,b,c,d$

一个整数，表示满足条件的对数

In the first example, there are $ 3 $ possible variants: $ (5, 3) $ , $ (10, 6) $ , $ (15, 9) $ . In the second example, there is no TV set meeting the constraints. In the third example, there is only one variant: $ (3, 2) $ .