Periodic Sequences - Definition & Examples

Define a sequence $\{x_n\}$ for positive integers $n$ such that $x_1=57, x_2 = 68, x_3=32$ and

$$x_n = x_{n-1}-x_{n-2} + x_{n-3}$$

for $n \ge 4$. Find all possible values of $x_{2013}$.

Source: Lexington Math Tournament