Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:2/2
K:Amin
['', '(cB)S AGAB TcBcA GECE TGFGB AGAB TcBca', 'Bcdf gc({d} (3cBc) Tagaa gede cdef gc({d}', 'gcac gc({d} (3cBc) BcdB AGAB cdea gede']  
X:1
L:1/8
M:2/2
K:Amin
 (cB)S |: AGAB TcBcA | GECE TGFGB | AGAB TcBca |1 gedB cedB :|2 gede cdef || g>c({d} (3cBc) gcac | 
 gc({d} (3cBc) Bcdf | gc({d} (3cBc) Tagaa | gede cdef || | gc({d} (3cBc) gcac | 
 gc({d} (3cBc) BcdB | AGAB cdea | gede cedSB |]  