Circle

Let $\mathrm{C}$ be a circle with radius $\sqrt{10}$ units and centre at the origin. Let the line $x+y=2$ intersects the circle $\mathrm{C}$ at the points $\mathrm{P}$ and $\mathrm{Q}$. Let $\mathrm{MN}$ be a chord of $\mathrm{C}$ of length 2 unit and slope $-1$. Then, a distance (in units) between the chord PQ and the chord $\mathrm{MN}$ is