How can i lose 2 stone in 2 months?

im 5 foot 4 inches and about 10 stone, ive put on 2 stone since ive been with my fiance and i would like to get back to how i was, need to do it in 2 months as im going on holiday. any suggestions?
thanks
Update: a stone is 14 pounds
Update 2: any food plans i could follow or easy exercise?
Update 3: im 20 by the way
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