24331

first I thought that the 2nd card must be bigger than the 1st, but in one of the answers it was lower and one it was higher.
then I tried 10 and 5 as the first 2 cards - but this did not work because it used 2 8 cards.
then I tried 9 and 6 but there were 2 9 cards.
then I tried 8 and 7 and this worked, the 7 cards were
8,7,13,10,6,12,9.
I tried 7 and 8 which nearly worked until the last card!
then I tried 6 and 9 and this worked
6,9,11,12,4,14,7
I carried on checking 5and 10, 4 and 11, 3 and 12, 2 and 13, 1 and 14 but they did not work.
If the first card was bigger than 10 it did not work.
I think there are only 2 answers.