The calculated distance (air line) between Kamyanka-Dniprovska and Mariupol is approximately 149 miles respectively 240 kilometers.
By car or train, the actual journey to Mariupol is certainly longer, as only the direct route (as the crow flies) between Kamyanka-Dniprovska and Mariupol has been calculated here.
Air line (approximately)
240 kilometers
130 nautical miles