2

Explanation:

This is one of the easy number series riddles in which you just need to replace the alphabets from A to Z with 1 to 26.

i.e

A = 1

B = 2

.......

.......

.......

Z = 26

So considering 1st part of equation

D = 4 , W=23 and sum = 27

In a similar fashion.

U=21, L=12 and sum = 33.

In last part

G = 7 , O = 15 and sum = 22

Therefore answer is 2.