import re

regex = r"((?:1[0-2]|0?[1-9]):[0-5][0-9]\s?(?:AM|PM|am|pm))\r?\n([F1]?)"

test_str = ("10:30 AM\n"
	"F\n"
	"10:40 AM\n\n"
	"10:50 AM\n"
	"F\n"
	"11:00 AM\n"
	"1\n"
	"11:10 AM\n\n"
	"11:20 AM\n"
	"1\n"
	"11:30 AM\n"
	"1\n"
	"11:40 AM\n"
	"1\n"
	"11:50 AM\n"
	"1\n"
	"12:00 PM\n\n"
	"12:10 PM\n"
	"1\n"
	"12:20 PM\n"
	"1\n"
	"12:30 PM\n"
	"1\n"
	"12:40 PM\n"
	"1\n"
	"12:50 PM\n"
	"1")

print(re.findall(regex, test_str, re.IGNORECASE))