### My issue

You are given 2 integers -

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A and

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C.

You need to find if there exists any

�

�

�

�

�

�

�

integer

�

B which meets the following condition

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B must be an integer

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B is the average of

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A and

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C.

For each test case, output

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B. If no such integer exists, output

−

1

−1

### My code

```
# Step 1: Read and understand the problem statement and sample test cases
# Click on 'Next' once you are ready to proceed.
t=int(input())
for i in range(t):
a, c = map(int, input().split())
b = (a+b)/2
if b
```

i dont know how to solve this