Find the smallest positive number from the following expressions:

\[ 10 - 3\sqrt{11}, \ 3\sqrt{11} - 10, \ 18 - 5\sqrt{13}, \ 51 - 10\sqrt{26}, \ 10\sqrt{26} - 51 \]

The original answer is in the form of k - m\sqrt{n}, please give the value of k + m.

Let's think step by step and output the final answer within \boxed{}.
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