Make Arithmetic Progression

You are given three positive integers $X, Y, $ and $Z$. In one operation, you can choose any one of these values, and change it to *any* integer of your choice. Find the **minimum** number of operations required to make the sequence $(X, Y, Z)$ an arithmetic progression. Note that $(X, Y, Z)$ is an arithmetic progression if and only if $Y-X = Z-Y$. ### Input - The first line of input contain