how many teams have used the stadium which hosted the gymnastics at the 1912 summer olympics – men's artistic individual all-around ?
SELECT DISTINCT COUNT attr_open var_uri attr_close where brack_open dbr_Gymnastics_at_the_1912_Summer_Olympics_–_Men's_artistic_individual_all-around dbp_venue var_x sep_dot var_x dbo_tenant var_uri sep_dot var_x a dbo_Stadium brack_close