Masyu (Moderate) Mystery Cache

Cache is not at the posted coordinates!

You are looking for a typical small cache that should not be difficult to find. 

You will however need to solve what is called a Masyu Puzzle to start on your journey to the cache.

Here are the rules of the Masyu Puzzle:

Masyu is a type of puzzle in which the solver is presented with a rectangular grid with black and white circles. The objective is to find a closed loop subject to the following constraints:

• The loop must pass through each black circle making a right angle and must continue straight for at least one additional square before and after the turn.
• The loop must pass straight through each white circle, but must make a 90 degree turn immediately before and/or immediately after passing through a white circle.
• There must be a single closed loop and it cannot pass through the same square twice.

This particular Masyu, meant to be of moderate difficulty of those I am presenting introduces the black circles. 



Credit: Thanks to Palmer Mebane for the creation of this puzzle.

You will notice that several squares have a letter associated with them. Those squares correspond with a number depending on how the line passes through the box, as can be seen in the key below, courtesy of CinderBankers. Of course, each letter could have two different values depending on which direction you are traveling along the line, so please start at the black circle in the upper left corner, and head right.  


So, you've completed the Masyu, and you've gathered the info for letters A through H. All that is left is a little math to get you the final coordinates. The container can be found at:

N 40 IJ.KLM W 75 NO.PQR

And you can find the values for I through R with the following equations:

I = D + B – E
J = E * H + B
K = A – B + G
L = E – F + B
M = G + H + B
N = F / D – C
O = D * C + A
P = D + D + G
Q = A * C + F
R = B / E + F