E: City
Santa decided to deliver presents to a city.
This city has the shape of a rectangle divided into $H$ rows and $W$ columns, and each cell contains one house that he has to deliver a present to.
The houses are numbered from $(1,1)$ to $(H,W)$ in row-major order.
Santa moves according to the following conditions:
He starts at cell $(S,T)$.
At each step, he can move to one of the four neighboring cells (north, south, east or west) as long as he stays inside the city.
He cannot visit any cell more than once.
Determine whether Santa can visit all the houses in the city or not.
Input
The input consists of a single line containing four integers $H$, $W$, $S$ and $T$ separated by a single space.
Output
If Santa can visit all the houses in the city, print "Yes". Otherwise, print "No".
Constraints
$2 \leq H, W \leq 10^9$
$1 \leq S \leq H$
$1 \leq T \leq W$
Sample Input 1
4 5 2 3
Sample Output 1
Yes
For example, he can follow this path:
Sample Input 2
3 3 1 2
Sample Output 2
No
