Civilians have been streaming out of the southern Ukrainian city whose recapture they had celebrated just weeks earlier but which has come under days of Russian artillery attack.The exodus from Kherson came as Ukraine solemnly remembered a Stalin-era famine and sought to ensure that Russia's war in Ukraine doesn't deprive others worldwide of its vital food exports.A line of trucks, vans and cars, some towing trailers or ferrying out pets and other belongings, stretched nearly a mile on the outskirts of the city on Saturday.Days of intensive shelling by Russian forces prompted a bittersweet exodus: many civilians were happy that their city had been won back, but lamented that they couldn't stay.Also on Saturday, Ukrainian President Volodymyr Zelensky hosted a summit in Kyiv with allied nations to launch a plan to export $US150 million worth of grain to countries most vulnerable to famine and drought."