10.1. Let $a, b, c$ be not necessarily distinct natural numbers such that the fractions $\frac{a+b}{c}, \frac{a+c}{b}, \frac{b+c}{a}$ are also natural numbers. Find all possible values of the sum $\frac{a+b}{c}+\frac{a+c}{b}+\frac{b+c}{a}$.