Time for patterns!

The pattern is: $n_1+n_2 - n_3 = n_4$ $~~~ ~~ ~~ ~ ~ ~$ $;[n_1 \text{is first number} , n_2 \text{ is second number} \ldots]$

$(3 + 3) - 2 = 4$

$(3+6) - 5 = 4$

$(1+4) - 3 = 2$

$? = \boxed{2}$

Add the first two numbers then subtract the third number form the sum obtained to get the final result, i.e.

$3+3-2 = 6-2 = 4$

$3+6 - 5 = 9-5 = 4$

$1+4-3 =5-3 = \boxed{2}$