Junior Mathematical Olympiad

Ahmed, Babeth, Casper, Daan, Emine, and Freek are sitting in a row, in this order. Ahmed and Babeth both write a positive integer on a piece of paper. Then Casper adds the numbers on the papers of Ahmed and Babeth and writes the result on his piece of paper. Afterwards, Daan adds the numbers on the papers of Babeth and Casper and writes the result on his piece of paper. Then Emine adds the numbers on the papers of Casper and Daan and writes the result on her piece of paper. Finally, Freek adds the numbers on the papers of Daan and Emine and writes the result on his piece of paper. Suppose that Emine wrote the number 19 on her paper, which number do you get if you add up the numbers on all papers?