A knitting shop orders yarn from three suppliers in Toronto, Montreal, and Ottawa. One month the shop ordered a total of 105 units of yarn from these suppliers. The delivery costs were $80, $45, and $63 per unit for the orders from Toronto, Montreal, and Ottawa, respectively, with total delivery costs of $5997. The shop ordered the same amount from Toronto and Ottawa. How many units were ordered from each supplier?

There were ? units ordered from Toronto, ? units from Montreal, and ? units from Ottawa.