KHARKIV, Ukraine —With his shadow of a moustache and baseball cap, Bohdan Levchykov would be your typical teenager anywhere if he didn't embody the tragedy of what has happened to a generation of young Ukrainians after nearly four years of war. His father Stanislav, a career soldier, was killed defending the country's second city Kharkiv just weeks after Russia invaded in 2022. On top of all they have been through, his mother Iryna, 50, was recently diagnosed with stage-three cancer of the uterus. Bohdan no longer knows anyone his age in his battered hometown of Balakliia, which was occupied by the Russian army from March to September 2022. It was later retaken by Ukrainian forces, but being only 70 kilometers (43 miles) from the front, it is still regularly shelled. "My mother and I came back a few days after the city was liberated, and there were no children left, no shops open, nothing," he recalled. Only a fraction of the pre-war population of 26,000 has trickled back, and most of them are old. The skate park and the banks of the Balakliika River where young people used to hang out