The ornamental design for an electronicpiano, as shown and described.
FIG. 1 is a perspective view of the front, top and right side of an electronic piano showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken line showing of the electronic piano is included for the purpose of illustrating portions of the electronic piano and forms no part of the claimed design.