It shall be the duty of the teachers of the public schools to prepare a program of patriotic exercises for the proper observance of Grand Army Flag Day. The department of elementary and secondary education shall prepare for the use of the schools a printed program providing for a uniform salute to the flag, to be used daily during the session of the school. The salute to the flag shall be as follows: “I pledge allegiance to the flag of the United States of America and to the republic for which it stands, one nation, under God, indivisible, with liberty and justice for all”.