procedure Sample_Input is
    X : Integer;
begin
    -- case 1:
    if X = 0 then
        null;
    elsif X = 1 then
        null;
    end if;

    -- case 2:
    if X = 0 then
        null;
    elsif X = 0 then
        null;
    end if;

    -- case 3:
    if X = 0 then
        if X = 0 then
            null;
        elsif X = 1 then
            if X = 2 then
                null;
            elsif X = 7 then
                null;
            end if;
        end if;
    elsif X = 1 then
        null;
    end if;

    -- case 4:
    if X = 0

       -- if this works then

        then
        if X = 0  -- if this works then
            then
            null;
        end if;

    end if;

    -- case 5:
    if Then_Position = 0 then
        If_Position := Position_Then;
    elsif Position_Then = 0 then
        Position_Then := If_Position;
    end if;

    -- case 6:
    if Check (" then ") then
        Call (" if ");
        Call (" then ");
    elsif Check (" -- ") then
        Call (" elsif ");
        Call (" then ");
    elsif Check (" -- ")  -- then
        then
        Call (" elsif ");
        Call (" then ");
    end if;

    -- case 7:
    if X = 0 and then X = 1 then
        if X = 0 and then X = 1 then
            if X = 0 and then X = 1 then
                null;
            end if;
        end if;
    end if;

end Sample_Input;