SELECT COUNT("Number of Screening") FROM table_72991 WHERE "Opening Film" = 'The Journey of Vaan Nguyen'
How many number of screenings have an opening film of the journey of vaan nguyen?
CREATE TABLE table_72991 (
    "Year" real,
    "Date (Opening)" text,
    "Date (Closing)" text,
    "Opening Film" text,
    "Number of Screening" text,
    "Award-Winning Film" text
)