how many teams have used the stadium which hosted the tennis at the 1924 summer olympics – men's singles ?
SELECT DISTINCT COUNT attr_open var_uri attr_close where brack_open dbr_Tennis_at_the_1924_Summer_Olympics_–_Men's_singles dbp_venue var_x sep_dot var_x dbo_tenant var_uri sep_dot var_x a dbo_Stadium brack_close