DECLARE FUNCTION M$ (n!)
CLS
DIM SHARED A AS STRING

INPUT "A = "; A
n = LEN(A)

FOR i = 1 TO n \ 2
   IF M(i) <> M(n - (i - 1)) THEN
      PRINT "NO"
      END
   END IF
NEXT

PRINT "YES"
END

FUNCTION M$ (n)
   M = MID$(A, n, 1)
END FUNCTION