a

a

a

a

a

b

b

b

b

b

b

c

d

d

d

e

e

e

e

f

f

f

f

g

g

h

h

h

i

j

k

k

l

l

l

m

m

m

m

m

m

n

p

p

p

p

r

s

s

s

t

t

t

v