10
11
12
12
13
13
14
14
14
15
15
15
a(a,10)
a(a,11)
a(a,12)
a(a,13)
a(a,14)
a(a,15)
a(b,12)
a(b,13)
a(b,14)
a(b,15)
a(c,14)
a(c,15)
