var
a: array[1..10] of integer;
i, n: integer;
begin
n := 8;
randomize;
for i := 1 to N do
begin
a[i] := random(21);
Write(a[i]:4);
end;
i := 2;
while i <= N - 2 do
begin
Swap(a[i], a[i + 1]);
i += 2
end;
Writeln;
for i := 1 to N do
Write(a[i]:4)
end.