1 --------------------------- ----------------- CUSIP No. 441560109 13G Page 7 of 8 Pages --------------------------- ----------------- EXHIBIT 1 TO SCHEDULE 13G February 14, 1997 MORGAN STANLEY GROUP INC. and MORGAN STANLEY ASSET MANAGEMENT LIMITED...

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CUSIP No.   000000000               13G                       Page 7 of 8 Pages
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                           EXHIBIT 1 TO SCHEDULE 13G


                               February 14, 1997



       XXXXXX XXXXXXX GROUP INC. and XXXXXX XXXXXXX ASSET MANAGEMENT LIMITED
     hereby agree that, unless differentiated, this Schedule 13G is filed on
     behalf of each of the parties.


       XXXXXX XXXXXXX ASSET MANAGEMENT LIMITED

   BY: /s/ XXXXX X. XXXXXX
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       Xxxxx X. Xxxxxx/Director Xxxxxx Xxxxxxx Asset Management Limited
                                    



       XXXXXX XXXXXXX GROUP INC.

   BY: /s/ XXXXXX X. XXXXXXX
       ------------------------------------------------------------------------
       Xxxxxx X. Xxxxxxx/Vice President Xxxxxx Xxxxxxx & Co. Incorporated