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;