Save VTK file mesh file with elements adjacency

General Discussion
1

I am currently using FreeFem++ to generate a VTK mesh, i.e.:

load “msh3”
load “iovtk”

int n=6;
mesh3 Th1 = cube(n, n, n);

savevtk(“cube-DG-mesh.vtk”, Th1);

Is there anyway for FreeFEM to generate the adjacency of elements as well?