Untitled

with sum as (
  select
    line_number,
    line::int + lead(line, 1) over w::int + lead(line, 2) over w::int as sum
  from day1
  window w as (order by line_number)
),
diff as (
  select
    sum::int - lag(sum, 1) over (order by line_number)::int as diff
  from sum
)
select
  count(*) filter (where diff > 0)
from diff
;