Convert from verst to X unit

Unit Definition (verst)
An obsolete Russian unit of length. It is defined as being 500 sazhen long, which makes a verst equal to 3500 feet (1066.8 metres).

Unit Definition (X unit)
The X-unit (symbol xu) is a unit of length formerly used to measure the wavelength of X-rays and gamma rays. The X-unit is approximately 1.0021×10-13 metre. Defined by the Swedish physicist Karl Manne Georg Siegbahn (1886-1978) in 1925, the X-unit could not at that time be measured directly; the definition was instead made in terms of the spacing between planes of the calcite crystals used in the measuring apparatus.