Among the players whose height is over 180, how many of them have a volley score of over 70?
height > 180; volley score refers to volleys; volleys > 70;
SELECT COUNT(DISTINCT t1.id) FROM Player AS t1 INNER JOIN Player_Attributes AS t2 ON t1.player_api_id = t2.player_api_id WHERE t1.height > 180 AND t2.volleys > 70