[Init] Solved solutions

cs/486A.cs

@@ -0,0 +1,13 @@
+using System;
+
+namespace _486A
+{
+	class Program
+	{
+		static void Main(string[] args)
+		{
+			ulong n = ulong.Parse(Console.ReadLine());
+			Console.WriteLine(n % 2 == 0 ? (n / 2).ToString() : "-" + ((n + 1) / 2).ToString());
+		}
+	}
+}