  This note contains a (short) proof of the following generalisation of the
Friedman--Mineyev theorem (earlier known as the Hanna Neumann conjecture): if
$A$ and $B$ are nontrivial free subgroups of a virtually free group containing
a free subgroup of index $n$, then $rank(A\cap B)-1\leqslant
n\cdot(rank(A)-1)\cdot(rank(B)-1)$. In addition, we obtain a
virtually-free-product analogue of this result.
