The ornamental design for a sanitarynapkin, as shown and described.
FIG. 1 is a front view of a sanitary napkin, showing our new design;
FIG. 2 is an enlarged cross-sectional view of a section thereof indicated by I, taken in the direction of line 2-2 in FIG. 1;
FIG. 3 is an enlarged cross-sectional view of a section thereof indicated by I, taken in the direction of line 3-3 in FIG. 1; and,
FIG. 4 is an enlarged cross-sectional view of a section thereof indicated by I, taken in the direction of line 4-4 in FIG. 1.
The broken lines shown in the drawings represent portions of the sanitary napkin that form no part of the claimed design. All sides not shown form no part of the claimed design.