a
b
c
d
e
f
g
h
1
wbs
p/n
1
2
3
4
5
6
2
 1 a
a
 c2: =if(len($a2) - len(substitute($a2, ".", "")) + 1 = c$1, $b2, "")
3
 1.1 b
b
4
 1.1.1 c
c
5
 1.1.2 d
d
6
 1.2 e
e
7
 1.3 f
f
8
 1.3.1 g
g