SELECT COUNT(most_recent) FROM table_name_56 WHERE height__m_ = "2770" AND first_time_as_hc_climb < 1992
Berapa tahun terakhir yang tinggi 2770 m dan pendakian HC sebelum 1992 naik?
CREATE TABLE table_name_56 (most_recent VARCHAR, height__m_ VARCHAR, first_time_as_hc_climb VARCHAR)