Okay, so how are we interpreting the notes? Are they mod 7, so

A = 0
G = 6
H = 7 ≡ 0 = A mod 7
I = 8 ≡ 1 = B mod 7

and so on? Could also be a microtonal system, among other interpretations.

If the former, though, the relevant congruences are

I = 8 ≡ 1 = B mod 7
L = 11 ≡ 4 = E mod 7
N = 13 ≡ 6 = G mod 7
P = 15 ≡ 1 = B mod 7
R = 17 ≡ 3 = D mod 7
S = 18 ≡ 4 = E mod 7
T = 19 ≡ 5 = F mod 7

So our final melody is

F D E E B A E E E F B G E

The octaves and rhythms aren’t specified, so I’m sure there’s a lot you could do with this. It’s also kinda neat that it ends in an authentic cadence (V-I, which in this case is G7 (G-B-(D)-F) to C (©-E-(G)).