I.10.30 Flux of the vector field

condition: Using Ostrogradsky's theorem, calculate the flow of the vector field \( \vec{a} \) through the indicated closed surface \( \sigma \). \( \vec{a}=3 x i-2 z j+y k, \sigma- \) part of the plane \( x+y+z=2 \), located in the first octant.