Do one of the following programming problems:
Minimum of 3
  Write a function called compute_min(value_1, value_2,
  value_3), which
  returns the minimum of the 3 floating point parameters to the function.
NOTE: Do not use the min function in this activity.
Passing Grade
  Write a function called passing_grade(grade), which
  returns a string,
  either 'perfect', 'pass',
  or 'fail', depending on the value of the specified
  grade.  Assume that grade is an integer in the range
  [0, 100].  If grade is 100, it should
  return 'perfect'.  If grade is less
  than 100 and greater than or equal to 70, it
  should return 'pass'.  If grade is less
  than 70, it should return 'fail'.