  A new discrete symmetry is shown to govern and simplify low-energy properties
of the supersymmetric N=2 gauge theory with an arbitrary gauge group. Each
element of the related symmetry group S_r, r being the rank of the gauge group,
represents a permutation of r electric charges available in the theory
accompanied by a concurrent permutation of r monopoles, provided the sets of
charges and monopoles are chosen properly. The superpotential is symmetric
under S_r. This symmetry strongly manifests itself for the degenerate case;
when the masses of r electric charges are chosen to be equal, then the masses
of r monopoles are necessarily degenerate as well, and vice versa. This
condition uniquely defines the vital for the theory VEV of the scalar field,
which makes all monopoles massless.
