public static void Main()
var n = int.Parse(Console.ReadLine());
var leftRight = (n - 1) / 2;
for (var i = 1; i <= (n-1) / 2; i++)
Console.Write(new string('-', leftRight));
var mid = n - 2 * leftRight - 2;
Console.Write(new string('-', mid));
Console.WriteLine(new string('-', leftRight));
for (var i = 1; i <= (n-1) / 2; i--)
Console.Write(new string('-', leftRight));
var mid = n - 2 * leftRight - 2;
Console.Write(new string('-', mid));
Console.WriteLine(new string('-', leftRight));