It will probably work OK though the other way around would have been better. You may find that the power supply runs rather hot so make sure it has plenty of space around it. If the router is drawing close to maximum current, the life of the power supply may well be reduced.
Whilst the 0.1a difference is unlikely to damage the router, if the power supply is a cheap one, it may not actually be very good at keeping to specs. Over time, that could reduce the life of the router.
As you can see, there are a lot of probably's and maybe's in the answer. In truth it is hard to be definitive without an in-depth analysis of the electronics. You are not going to immediately kill either the router or the power supply but there is a small chance that either or both of them will have reduced lifespans.
Thank you, very much sir. Probably i should buy a more suitable adapter. – AskingME – 2015-06-22T05:56:27.327