f=open("studentslist", "r")
f1 =open("studentpassed", "r")
def convert_to_set(file):
    file_set=set()
    for names in file:
         file_set.add(names.rstrip("\n"))
    return file_set
student_set=convert_to_set(f)
student_passed=convert_to_set(f1)
print(student_set-student_passed)