PROGRAMMING:Find the value of 1-3 + 5... - 99 + 101
Find the value of 1-3 + 5-7 +... - 99 + 101.
###Output format:
Output the calculation results in the order of "s = result" in one line.
###Output example:
```out
s=51
```
answer：If there is no answer, please comment
###Output format:
Output the calculation results in the order of "s = result" in one line.
###Output example:
```out
s=51
```
answer：If there is no answer, please comment