The mayors of Seattle and Washington, D.C., have a bet on the outcome of Sunday's playoff game between Washington and the Seahawks.

Seattle Mayor Mike McGinn has proclaimed “Seahawks Blue Friday,” asking all city residents to wear blue Friday to show their support as the Seahawks head into the NFL playoffs Sunday against the Washington Redskins.

In addition, McGinn has a bet on the game with Washington D.C. Mayor Vincent Gray. Terms of the wager: the mayor of the city with the losing team must fly the victor’s flag over his city’s city hall for a day.

According to the Associated Press, Gray said he’s confident it will be Seattle flying Washington’s flag. He says the Seahawks have not won a road playoff game since 1983. But the Redskins have also lost their last two playoff appearances against the Seahawks in 2005 and 2007.