  Let $L_N = L_{MBM}(X_1,..., X_N; Y_1,..., Y_N)$ be the minimum length of a
bipartite matching between two sets of points in $\mathbf{R}^d$, where
$X_1,..., X_N,...$ and $Y_1,..., Y_N,...$ are random points independently and
uniformly distributed in $[0,1]^d$. We prove that for $d \ge 3$,
$L_N/N^{1-1/d}$ converges with probability one to a constant $\beta_{MBM}(d)>0$
as $N\to \infty $.
