Circle Problem

Let $\mathcal{R}$ be the circle centered at $(0,0)$ with radius 10. The lines $x = 6$ and $y=5$ divide $\mathcal{R}$ into four regions $\mathcal{R}_1,\mathcal{R}_2,\mathcal{R}_3,$ and $\mathcal{R}_4$. Let $[\mathcal{R}_i]$ denote the area of region $\mathcal{R}_i$. If $[\mathcal{R}_1] > [\mathcal{R}_2] > [\mathcal{R}_3] > [\mathcal{R}_4],$then find $[\mathcal{R}_1] - [\mathcal{R}_2] - [\mathcal{R}_3] + [\mathcal{R}_4]$.