Consider an undirected graph

G

$=$

$($

V

$,$

E

$)$

with

n

$=$

$\backslash |$

V

$\backslash |$

and

m

$=$

$\backslash |$

E

$\backslash |$

$.$ The degree of a vertex is the number of edges incident on that vertex. Let

d

i

be the degree of vertex

v

i

$.$ Show that

n

$$

$1$

d

i

$=$

$2$

m