35. For any three real numbers $a, b, c$, let $M\{a, b, c\}$ represent the average of these three numbers, and let $\min \{a, b, c\}$ represent the smallest of these three numbers. If
$$
M\{2 x+y+2, x+2 y, 2 x-y\}=\min \{2 x+y+2, x+2 y, 2 x-y\},
$$

then $x+y=$ . $\qquad$
answer: -4