===== PascalABC.NET =====

begin

 var n := ReadInteger('n =');

 var a := MatrRandom(n, n, 10, 99);

 a.Println(3);

 Writeln;

 for var i := 0 to n - 1 do

   Swap(a[i, i], a[i, n - i - 1]);

 a.Println(3)

end.