I am trying to have excel return a value to me based on a number that it
compares to a fixed table of numbers. See example below (the small x is the
value that I am trying to retrieve, this will be an R or L):

X Y PTM#
0.54 x 0.58 1
0.82 x 0.50 2
0.66 x 0.73 3
0.06 x 0.27 4
0.03 x 0.13 5


Here is the Table:
X Y PTM
0.29 R 0.66 1
0.74 R 0.49 2
0.89 L 0.70 3
0.60 R 0.39 4
0.88 R 0.31 5


What function/formula should I use?