WRITE(Messagebox) NthRoot(5, 34)
WRITE(Messagebox) NthRoot(10, 7131.5^10)

FUNCTION NthRoot(n, A)
   REAL :: prec = 0.001

   IF( (n > 0) * (A > 0) ) THEN
       NthRoot = A / n
       DO i = 1, 1/prec
         x = ((n-1)*NthRoot + A/(NthRoot^(n-1))) / n
         IF( ABS(x - NthRoot) <= prec ) THEN
             RETURN
         ENDIF
         NthRoot = x
       ENDDO
   ENDIF

   WRITE(Messagebox, Name) 'Cannot solve problem for:', prec, n, A
END