Infinite number of  point size masses, each 1kg are placed along the x-axis at $\mathrm{x}=\pm 1\mathrm{m},\pm 2\mathrm{m},\pm 4\mathrm{m},\pm 8\mathrm{m},\pm 16\mathrm{m}..........$ The gravitational potential in terms of gravitational constant G at the origin (x=0) is (take gravitational potential at infinity zero.)