The calculated distance (air line) between Gresovskiy and Pervomayskoye is approximately 50 miles respectively 80 kilometers.
By car or train, the actual journey to Pervomayskoye is certainly longer, as only the direct route (as the crow flies) between Gresovskiy and Pervomayskoye has been calculated here.
Air line (approximately)
80 kilometers
43 nautical miles