st: List[Tree] = List(
(, ,),
(NP (NP (CD one)) (PP (IN of) (NP (NNP M) (CC and) (NNP N)))),
(NNP P),
(CD one),
M,
N,
(NN P),
P,
(NN number),
number,
(VP (VBZ divides) (NP (NNP MN))),
(VP (VBZ divides) (NP (NP (CD one)) (PP (IN of) (NP (NNP M) (CC and) (NNP N))))),
(NP (DT a) (JJ prime) (NN number) (NN P)),
(NP (NNP MN)),
(NP (NNP P)),
divides,
and,
(ROOT (S (SBAR (IN if) (S (NP (DT a) (JJ prime) (NN number) (NN P)) (VP (VBZ divides) (NP (NNP MN))))) (, ,) (NP (NNP P)) (VP (VBZ divides) (NP (NP (CD one)) (PP (IN of) (NP (NNP M) (CC and) (NNP N))))))),
of,
(NP (NNP M) (CC and) (NNP N)),
(NNP M),
if,
(NNP N),
(JJ prime),
prime,
a,
MN,
(PP (IN of) (NP (NNP M) (CC and) (NNP N))),
(NP (CD one)),
(SBAR (IN if) (S (NP (DT a) (JJ prime) (NN number) (NN P)) (VP (VBZ divides) (NP (NNP MN))))),
(S (NP (DT a) (JJ prime) (NN number) (NN P)) (VP (VBZ divides) (NP (NNP MN)))),
one,
,,
...