Uses Crt;
Var
a: Array [1 .. 10] Of Integer;
Flag, i, k, n: Integer;
Begin
ClrScr;
Write('Количество элементов таблицы, n=');
ReadLn(n);
For i := 1 To n Do
Begin
Write('a[', i, ']=');
ReadLn(a[i]);
End;
i := 1;
While i <= n - 1 do
Begin
Flag := 0;
If ((a[i] = 1) and (a[i + 1] = 0)) or ((a[i] = 0) and (a[i + 1] = 1)) Then
Flag := 1
Else
Begin
Write('нет');
Flag := 0;
ReadLn;
Halt;
End;
i := i + 2;
End;
If Flag = 1 Then
Write('Чередование существует');
ReadLn;
End.