Solvable D_2-Groups

Let G be a finite group, Irr_1(G) be the set of nonlinear irreducible characters of G and cd_1(G) the set of degrees of the characters in Irr_1(G). A group G is said to be a D_2-group if |cd_1(G)| =|Irr_1(G)|-2. In this paper, we give a complete classification of solvable D_2-groups.