B2. 56 There is one row with only pears. Now we count the rows with at least one apple. In such a row, all apples must be directly next to each other, because there can never be a pear between two apples. For example, if we want to choose 8 apples, they can be in positions $1 \mathrm{t} / \mathrm{m} 8$, in positions $2 \mathrm{t} / \mathrm{m} 9$, or in positions $3 \mathrm{t} / \mathrm{m} 10$, a total of three possibilities. In this way, we find 1 row for 10 apples, 2 rows for 9 apples, 3 rows for 8 apples, and so on, up to 10 rows for 1 apple. In total, we find $1+2+3+\cdots+10=55$ rows with at least one apple. The total number of rows is therefore $55+1=56$.
B2. Karel has a large quantity of apples and pears. He wants to choose ten pieces of fruit from these and arrange them in a row. This must be done in such a way that there is never a pear between two apples. The rows AAAAAAAAAA and AAPPPPPPPP are allowed, for example, but the rows AAPPPPPPPA and APPPPPPPAA are not.

How many rows can Karel make like this?