I claim the ornamental design for a bin, as shown and described.
FIG. 1 is a front elevational view of a bin;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a right side elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The dash-dot lines represent the bounds of the claimed design, while all other broken lines are directed to environment; the dash-dot lines and other broken lines in the Figures are for illustrative, environmental purposes only and form no part of the claimed design.