Convert from vershok to zeptometer

Unit Definition (vershok)
Obsolete Russian weights and measures were used in Imperial Russia and after the Russian Revolution until they were replaced in the Soviet Union by a metric system in 1924.

Unit Definition (zeptometer)
The zeptometre (or zeptometer), symbol: zm, is an SI unit of metric length measurement. 1 zeptometre is 1e-21 metres, which is a very small distance