Q4 (20pt): Ask user enter a sentence, and find out the second most appeared character from the sentence. (Print all if there are multiple character is rank second) Example output 1 (Input is in bold): Enter a sentence: Hello world The second most appeared character is o Example output 2 (Input is in bold): Enter a sentence: HAA BBB A CCCC The second most appeared character is A B Example output 2 (Input is in bold): Enter a sentence: A b c d e The second most appeared character is none

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