How many lunges a day to drop 3 pants sizes in 3 months?

I have a flat stomach and everything, but my thighs are just too big! I recently started doing squats and lunges. How many lunges and squats should I do to accomplish this? I have a healthy diet of about 1500 calories per day, and I do sit ups and climb the stairs 50 times a day. But nothing seems to slim my legs. I heard these Hlp, I just have no idea how many to do. Help!?!?!?!? Thanks.(: