This is an 8 slot sequencing game. We are placing O in 5 and M in 7.
We are trying to determine the number of variables whose placement is fixed after the new condition is given.
I must be last of the remaining variables, so we place this in slot 8.
Of the now remaining 5 variables, G must be last, so we place this variable in slot 6 (the last available slot).
Of H, N, K, and J, we cannot determine which variables must go in which slots. It is for this reason that we can only determine the position of 2 variables.