How much weight will I lose in a week if I do this? Pl pl pl answer?

If I eat watermelon and nothing else only for a week, ie - consuming half a watermelon daily. And at the same time daily for a week use the bike and burn 150 or 200 cals. I want to do this for just a week because my birthday is in a week and I'd love to see some difference, how much would I roughly lose in a week in kgs? Please give me an appropriate direct answer, thanks so much :)