13 Floors

Bill is responsible for labeling all the floors on a new skyscraper. He's superstitious, so he wants to skip floor 13 while labeling the floors. This means that the $12^\text{th}$, $13^\text{th}$, and $14^\text{th}$ floors should be labeled $12$, $14$, and $15$, respectively. Given the true floor number, can you tell Bill what to label that floor?

The input is a single positive integer $x \leq 1\,000\,000$ representing the true floor number.

The output is a single positive integer, which is the label for the corresponding floor in the input.