Thousands of people flocked to Kyiv’s main post office Tuesday to snap up a stamp commemorating the standoff between Ukrainian forces on Snake Island and the flagship of Russia’s Black Sea fleet, the Moskva, which Ukraine has since claimed to have sunk with cruise missiles.

The collector's item, which went on sale on April 13, commemorates the incident with an image of a Ukrainian soldier raising his middle finger in an obscene gesture to the Moskva warship with a text that reads: "Russian warship, f**k you."

The artwork for the stamp was created by artist Boris Groh in honor of Ukrainian border guard Roman Gribov, who along with his 12 companions was captured on the small island of Zmiinyi (Snake Island) after refusing to surrender.