Find the Area of the Surface $S$ Where $S$ Is the Part of the Sphere

Find the area of the surface $S$ where $S$ is the part of the sphere $x ^ { 2 } + y ^ { 2 } + z ^ { 2 } = 16$ that lies inside the cylinder $x ^ { 2 } - 4 x + y ^ { 2 } = 0$ .