A tree had 1000 leaves before the onset of the dry season, when it sheds all its leaves. In the first week of the dry season, the tree shed 2/5 of the leaves. In the second week, it shed 40% of the remaining leaves.  In the third week, the tree shed 3/4 times as many leaves as it shed on the second week. Calculate the number of leaves the tree hadn't shed by the third week.
Please reason step by step, and put your final answer within \boxed{}.
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