PROGRAMMING:Family photo of Xiao Ming
Xiao Ming, his father and mother went to Qingdao and took a lot of photos. After going home, Xiao Ming put all his photos into his album, then put all the photos of his mother into his mother's album from the rest of the photos, and finally put the rest into his father's album.
After Dad came back, he took out all the photos of Xiaoming and his mother in the album and put them in his album.
After mom came back, she took out all the photos of Xiaoming and dad in the album and put them in her album.
Excuse me: does Xiao Ming take more pictures with his mother or with his father?
Suppose Xiao Ming and his mother have more pictures than his father. Please write a program to find the value of $$Z $.
####Input format
```in
x y
```
####Output format
```out
z
```
Tip: if Xiaoming and his mother take more photos than his father, then $$s $$is a positive number; If it is the same, it is zero; If less, it is negative.
answer：If there is no answer, please comment
After Dad came back, he took out all the photos of Xiaoming and his mother in the album and put them in his album.
After mom came back, she took out all the photos of Xiaoming and dad in the album and put them in her album.
Excuse me: does Xiao Ming take more pictures with his mother or with his father?
Suppose Xiao Ming and his mother have more pictures than his father. Please write a program to find the value of $$Z $.
####Input format
```in
x y
```
####Output format
```out
z
```
Tip: if Xiaoming and his mother take more photos than his father, then $$s $$is a positive number; If it is the same, it is zero; If less, it is negative.
answer：If there is no answer, please comment