Curly braces { } contain the minimum and maximum number of matches. For example, 10{1,2}1
will match both "101" and "1001" but not "10001" as the minimum number of matches is 1 and the maximum number of matches is 2. He[Ll]{2,}o
will match "HeLLo" and "HellLLLllo" and any such silly variation of "hello" with lots of L’s, since the minimum number of matches is 2 but the maximum number of matches is not set — and therefore unlimited!