What is CFG of the following language over the alphabet {2, 4, 6}: The language contains strings of 2's, 4's and 6's, such that in each string 2's are followed by 4's which are followed by 6's, and the number of 2's and 4's equal to the number of 6's. Examples: 244666 (is accepted, because number of 2's and 4's is three and number of 6's is three): 224444666666 (is accepted) 22246666 (is accepted) 2466 (is accepted) 2246 (is not accepted, because number of 2's and 4's is three but number of 6's is one)