Find the positive integer solutions of the equation
\[ \left(1 + \frac{1}{a}\right)\left(1 + \frac{1}{b}\right)
\left(1+ \frac{1}{c}\right) = 2. \]
[Both this problem and the problem
Proximity come from the Hungarian magazine KoMaL and you'll
find many other challenging problems in English on
the KoMal website
]