3. $A, B, C$ three people pick watermelons. The sum of the number of watermelons picked by $A$ and $B$ is 6 less than that picked by $C$; the sum of the number of watermelons picked by $B$ and $C$ is 16 more than that picked by $A$; the sum of the number of watermelons picked by $C$ and $A$ is 8 more than that picked by $B$. Then the product of the number of watermelons picked by each person is $\qquad$