50kg seems rather low, How tall are you?. are you sure it's a reasonable goal?
3 months isn't really long enough for that sort of loss either, not unless you're prepared to put in hours a day for exercise and eat absolutely healthy (most lack the dedication that sort of shift requires).
You can't choose which fat stores your body will use, gotta bring the sum total down and accept that it comes off where it comes off.
You either need to get yourself a personal trainer who missed their calling as a drill instructor or do a fair bit of research and drive yourself with a cast iron will (I'd suggest you look at resistive strength training, HIIT cardio, Macronutrient ratios, calorie control, Resting metabolic rate and probably a dozen more things that don't occur right now)
Tourny