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Twelve Letters ABCDEFGHIJ Arrangement

2175ExpertCombinatoricsCounting Principles

2025 AIME I · 2025

The twelve letters A, B, C, D, E, F, G, H, I, J, K, and L are randomly grouped into six pairs of letters. The two letters in each pair are placed next to each other in alphabetical order to form six two-letter words, and then those six words are listed alphabetically. For example, a possible result is AB, CJ, DG, EK, FL, HI. The probability that the last word listed contains G is $\frac{m}{n}$, where $m$ and $n$ are relatively prime positive integers. Find $m+n$.
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