The mass of the object on the horizontal plane is m, and the horizontal constant force F moves L; then the external force is removed, and the object moves 2L and stops?

The mass of the object on the horizontal plane is m, and the horizontal constant force F moves L; then the external force is removed, and the object moves 2L and stops?

The work done by F is equal to the work done by friction, so f × L = f × 3L
So f = f / 3