The lemon tree!!

There was a lemon tree in the park.A poor man wanted to have lemons from the lemon tree.But there were seven guards for the protection of the tree.The man had an idea,he went to each of the seven guard and told that,he will bring some lemons from the tree and give half the lemons he had and take one back from it.he told this to all guards and brought some lemons.when he returned he had only two lemons left with him...

So initially how many lemons did he took from the tree??

For example:if he bought 100lemons from the tree then he would give 50 to the first guard and take 1 back from that ,so the man will have51 lemons left,then doing the same thing with the other guards..

If u like my problem please share it.