When the second intermediate period of egypt is the  ubaid period in mesopotamia how many early calcolithics are there?
CREATE TABLE "table1_23537091_1" (
  "copper_age" text,
  "chalcolithic_4500_bc_3300_bc" text,
  "early_chalcolithic" text,
  "4500_bc_4000_bc" text,
  "ubaid_period_in_mesopotamia" text
);
SELECT COUNT("early_chalcolithic") FROM "table1_23537091_1" WHERE "ubaid_period_in_mesopotamia"='Second Intermediate Period of Egypt';