what is the flagbearer of the guyana at the 2000 summer olympics and guyana at the 2004 summer olympics
SELECT DISTINCT var_uri where brack_open dbr_Guyana_at_the_2000_Summer_Olympics dbp_flagbearer var_uri sep_dot dbr_Guyana_at_the_2004_Summer_Olympics dbp_flagbearer var_uri brack_close