The standard deviation of the salaries of the employees at a company is $ thousand. If all the employees receive a $ thousand raise, will the standard deviation decrease, increase, or stay the same?

The mean of a data-set is given by the sum of it's observations, divided by the number of observations.
The standard deviation is given by the square root of the sum of the differences squared of each observation and the mean, divided by the one less than the number of values.

If all observations are increased by a value x, the mean will also increase by x.
In the standard deviation, at the sum of the differences squared of each observation and the mean, each observation is increased by x, as is the mean, thus, the sum stays the same, while the standard deviation also stays the same.

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The standard deviation of the salaries of the employees at a company is ​$ thousand. If all the employees receive a ​$ thousand​ raise, will the standard deviation​ decrease, increase, or stay the​ same?