  We define an invariant $l(M,W,\omega)$ for Lagrangian submanifold and prove
that if the Lagrangian submanifold is embedded in the ball of radius $r_0$,
then $l(M,W,\Omega)$ must be smaller than $4\pi t_0^2$. This improves Gromov's
Lagrangian embedding theorem.
