Logical Operations
    Logical Expressions              evaluate to either .TRUE.   or  .FALSE.
    Example 1: Given that X has a value of 3.0, Y has a value of  5.0, Z has a
   value of 10.0, and FLAG is a logical variable with .FALSE. Value, evaluate
   the following  FORTRAN expression:
       
                      .NOT.FLAG .AND. X*Y .GT. Z .OR. X+Y .GT. Z
          Priority
Arithmetic expressions
Relational expressions
Logical expressions
.NOT.FLAG .OR. FLAG
.NOT. .NOT. FLAG
 X .GT. Y – Z / 2.0