Name the number of opponent with arrowhead stadium
{'header': ['Week', 'Date', 'Opponent', 'Result', 'Game site', 'Record', 'Attendance'], 'page_title': '1985 Seattle Seahawks season', 'section_title': 'Schedule', 'caption': 'Schedule', 'rows': [['1', 'September 8, 1985', 'at Cincinnati Bengals', 'W 28-24', 'Riverfront Stadium', '1-0', '51625'], ['2', 'September 15, 1985', 'at San Diego Chargers', 'W 49-35', 'Jack Murphy Stadium', '2-0', '54420'], ['3', 'September 23, 1985', 'Los Angeles Rams', 'L 24-35', 'Kingdome', '2-1', '63292'], ['4', 'September 29, 1985', 'at Kansas City Chiefs', 'L 7-28', 'Arrowhead Stadium', '2-2', '50485'], ['5', 'October 6, 1985', 'San Diego Chargers', 'W 26-21', 'Kingdome', '3-2', '61300'], ['6', 'October 13, 1985', 'Atlanta Falcons', 'W 30-26', 'Kingdome', '4-2', '60430'], ['7', 'October 20, 1985', 'at Denver Broncos', 'L 10-13 OT', 'Mile High Stadium', '4-3', '74899'], ['8', 'October 27, 1985', 'at New York Jets', 'L 14-17', 'The Meadowlands', '4-4', '69320'], ['9', 'November 3, 1985', 'Los Angeles Raiders', 'W 33-3', 'Kingdome', '5-4', '64060'], ['10', 'November 10, 1985', 'at New Orleans Saints', 'W 27-3', 'Louisiana Superdome', '6-4', '47365'], ['11', 'November 17, 1985', 'New England Patriots', 'L 13-20', 'Kingdome', '6-5', '60345'], ['12', 'November 25, 1985', 'at San Francisco 49ers', 'L 6-19', 'Candlestick Park', '6-6', '57482'], ['13', 'December 1, 1985', 'Kansas City Chiefs', 'W 24-6', 'Kingdome', '7-6', '52655'], ['14', 'December 8, 1985', 'Cleveland Browns', 'W 31-13', 'Kingdome', '8-6', '58477'], ['15', 'December 15, 1985', 'at Los Angeles Raiders', 'L 3-13', 'Los Angeles Memorial Coliseum', '8-7', '77425']]}