The ornamental design for a pan, as shown and described.
FIG. 1 is a front side perspective view of a pan showing the new design;
FIG. 2 is a left side view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear side view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof;
FIG. 8 is a bottom perspective view thereof;
FIG. 9 is an enlarged front side perspective view of the circled portion of the pan in FIG. 1; and,
FIG. 10 is an enlarged bottom front side perspective view of the circled portion of the pan in FIG. 8.
The broken lines shown in the drawings depict portions of the pan that form no part of the claimed design. The broken lines encircling portions of the claimed design that are illustrated in the enlargements form no part of the claimed design.