Table schema:
CREATE TABLE table_29474481_4 (french_head_of_state VARCHAR, head_of_mission VARCHAR)

Question: How many French heads of state have a head of mission of Xavier Daufresne de la Chevalerie?
SQL: SELECT COUNT(french_head_of_state) FROM table_29474481_4 WHERE head_of_mission = "Xavier Daufresne de la Chevalerie"