A machine is programmed to cut lengths of string from a uniform string coming up continuously from a factory belt. The lengths are all measured in metres, and are as follows:

$$

\frac{21^{3}}{100} ; \quad \frac{22^{3}}{100} ; \quad \frac{23^{3}}{100} ; \ldots, \frac{120^{3}}{100} .

$$

Calculate the total length of the string cut, giving your answer in kilometres.