A synchronous password token has to operate at the same pace as the receiver. That is$,$ the token has to advance to the next random number at the same time the receiver advances. Because of clock imprecision, the two units will not always be perfectly together; for example, the token$$s clock might run $1$ second per day slower than the receiver$$s$.$ Over time, the accumulated difference can be significant. Suggest a means by which the receiver can detect and compensate for clock drift on the part of the token.