2. The following EBNF rules describe the syntax of decimal integer constants in C99. Write a single Perl pattern (regular expression) that matches these constants. Simplif your pattern as much as possible. integer-constant: decimal-constant integer-suffixopt decimal-constant: nonzero-digit decimal-constant digit integer-suffix: unsigned-suffix long-suffixopt unsigned-suffix long-long-suffi:x long-suffix unsigned-suffixopt long-long-suffix unsigned-suffixopt unsigned-suffix: one of long-suffix: one of 1 long-long-suffix: one of