Sean $a = \frac{x}{y} +\frac{y}{z} +\frac{z}{x}$, $b = \frac{x}{z} +\frac{y}{x} +\frac{z}{y}$ y $c = \left(\frac{x}{y} +\frac{y}{z} \right)\left(\frac{y}{z} +\frac{z}{x} \right)\left(\frac{z}{x} +\frac{x}{y} \right)$. El valor de $|ab-c|$ es: