I claim the ornamental design for a bin, as shown and described.
FIG. 1 is a front/right/top perspective view of a bin;
FIG. 2 is a rear/left/bottom perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a right side elevational view thereof (a left side elevational view would be a mirror image thereof);
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines immediately adjacent the shaded areas represent the bounds of the claimed design, while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.