PROGRAMMING:green grassland
As the sheep and sheep fight with gray wolf every day, the grass on the grassland is neglected, so they find a grass planting teacher$$ 2 $$to help plan the grass planting project$$ Bear$$_ $$ 2 $$the grassland is directly divided into $$n * m $$squares. On the first day, the grass is sown in $$(x, y) $. Every other day, the grass will make the adjacent grid grow grass.
In other words, if there is grass in $$(x, y) $, then the next day $$(x + 1, y) (x, y + 1) (x-1, y) (x, Y-1) $$will also grow grass
Now, the sheep want to know how many days later the grassland will be covered with grass.
###Input format:
Input the number of sample groups in the first line $$t (1 < = T < = 100)$$
Each group of data input four positive integers $$n, m, x, y (1 < = n, m < = 10 ^ 9,1 < = x, y < = n) $$. They are the specifications of Qingqing grassland and $$bear $$$U$$ Where to plant grass on the first day.
###Output format:
For each group of data, please output the number of days needed for the grassland to be full of grass.
###Input example:
```in
two
2 2 1 1
3 3 2 2
```
###Output example:
```out
two
two
```
###Tips:
20% data, $$1 < = n, m < = 10$$
40% data, $$1 < = n, m < = 10 ^ 3$$
60% data, $$1 < = n, m < = 10 ^ 4$$
For 100% of data, $$1 < = n, m < = 10 ^ 9 $$< br > < br > < br > < br > < br > is used
answer：If there is no answer, please comment
In other words, if there is grass in $$(x, y) $, then the next day $$(x + 1, y) (x, y + 1) (x-1, y) (x, Y-1) $$will also grow grass
Now, the sheep want to know how many days later the grassland will be covered with grass.
###Input format:
Input the number of sample groups in the first line $$t (1 < = T < = 100)$$
Each group of data input four positive integers $$n, m, x, y (1 < = n, m < = 10 ^ 9,1 < = x, y < = n) $$. They are the specifications of Qingqing grassland and $$bear $$$U$$ Where to plant grass on the first day.
###Output format:
For each group of data, please output the number of days needed for the grassland to be full of grass.
###Input example:
```in
two
2 2 1 1
3 3 2 2
```
###Output example:
```out
two
two
```
###Tips:
20% data, $$1 < = n, m < = 10$$
40% data, $$1 < = n, m < = 10 ^ 3$$
60% data, $$1 < = n, m < = 10 ^ 4$$
For 100% of data, $$1 < = n, m < = 10 ^ 9 $$< br > < br > < br > < br > < br > is used
answer：If there is no answer, please comment