Harry Potter's problem

[kate]

Harry knows that

[tex]\begin{array}{cccccc} L & U & M & I & N & A \\ & U & M & I & N & A \\ & & M & I & N & A \\ & & & I & N & A \\ & & & & N & A \\ & & & & & A \\ \hline \\ M & L & 9 & U & 7 & A \end{array}[/tex]

Help Harry find the sum of the letters: [tex]L + U + I + M + I + N + A = ?[/tex]

[Harry]

If Harry Potter said that the sum of the letters was 31 would he guess?