What was the sum of Revenue ($M), when the Debt as % of value was higher than 27, and the Operating income($m) was 77?
CREATE TABLE "2008_rankings" (
  "rank" real,
  "team" text,
  "country" text,
  "value_m" real,
  "debt_as_pctof_value" real,
  "pct_change_on_year" text,
  "revenue_m" real,
  "operating_income_m" real
);
SELECT SUM("revenue_m") FROM "2008_rankings" WHERE "debt_as_pctof_value">27 AND "operating_income_m"=77;