  Let $h$ be a positive integer and $A, B_1, B_2,\dots, B_h$ be finite sets in
a commutative group. We bound $|A+B_1+...+B_h|$ from above in terms of $|A|,
|A+B_1|,\dots,|A+B_h|$ and $h$. Extremal examples, which demonstrate that the
bound is asymptotically sharp in all the parameters, are furthermore provided.
