By mid-1950, North Korean forces numbered between 150,000 and 200,000 troops, organized into 10 infantry divisions, one tank division, and one air force division, with 210 fighter planes and 280 tanks, who captured scheduled objectives and territory, among them Kaesong, Chuncheon, Uijeongbu, and Ongjin. What type of naval ships did the South and North Koreans have?