For x $\in$ R, let [x] denote the greatest integer $\le$ x, then the sum of the series $\left[-\frac{1}{3}\right]+\left[-\frac{1}{3}-\frac{1}{100}\right]+\left[-\frac{1}{3}-\frac{2}{100}\right]+..........+\left[-\frac{1}{3}-\frac{99}{100}\right]$is :