import java.util.Scanner; public class Test { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int x = sc.nextInt(), y = sc.nextInt(), r = sc.nextInt(), z = 0, w; if(x < 0){x *= -1;} if(y < 0){y *= -1;} while(z*z*2 <= r*r){z++;} w = z; if(z*(z-1)*2 > r*r){w--;} System.out.println(x+y+z+w); } }