Step 1 :\(PV = nRT\)
Step 2 :\(n = \frac{PV}{RT}\)
Step 3 :\(n = \frac{66.6 \mathrm{~atm} \times 8 \mathrm{~L}}{0.0821 \frac{\mathrm{L\cdot atm}}{\mathrm{mol\cdot K}} \times (273.15 + 202.6)^{\circ} \mathrm{K}}\)