Blindfolded Man

You are blindfolded and taken to a room, where you are asked to kneel. You feel hundreds of circular discs lying in front of you. You are told that one side of each disc is painted red, and the other, green. There are exactly 129 discs that currently are red side up.
You have to divide the discs into two groups(both groups need not have same number of discs), such that each group has the same number of discs showing the red colour.

Divide the discs into 2 partitions such that 1st part gets 129 discs. Assume that there are k discs showing RED up(so, 129-k discs are showing GREEN up. The 2nd part will have 129-k discs showing RED up.). Now flip all the 129 discs from 1st part. Now there wud b same number of discs(129-k) that are turned RED up in both parts.