Per Curiam.
The time for appellant to serve and file its brief expired August 8. The brief was served on opposing counsel August 11, and filed August 13. Respondent's motion to dismiss on the ground that the brief was not served and filed within the time allowed by rule must be sustained. Rule 21, 42 Wyo. 536.
Appellant has filed an affidavit showing that as the result of an error in calculation it was thought that the time for serving and filing the brief did not expire until August 13. We cannot hold that this mistake would justify a suspension of the rule. See, Cronkhite v. Bothwell, 3 Wyo. 739, 31 P. 400; Ford v. Townsend, 22 Wyo. 397, 143 P. 356, and cases cited.
Dismissed.