  We show that for any coprime integers $\lambda_1 , \ldots , \lambda_k$ and
any finite $A \subset \mathbb{Z}$, one has $$|\lambda_1 \cdot A + \ldots +
\lambda_k \cdot A| \geq (|\lambda_1| + \ldots + |\lambda_k|)|A|- C,$$ where $C$
only depends on $\lambda_1 , \ldots , \lambda_k$.
