{"raw_statement":[{"iden":"problem statement","content":"You are given a $4$\\-character string $S$ consisting of uppercase English letters. Determine if $S$ consists of exactly two kinds of characters which both appear twice in $S$."},{"iden":"constraints","content":"*   The length of $S$ is $4$.\n*   $S$ consists of uppercase English letters."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$S$"},{"iden":"sample input 1","content":"ASSA"},{"iden":"sample output 1","content":"Yes\n\n$S$ consists of `A` and `S` which both appear twice in $S$."},{"iden":"sample input 2","content":"STOP"},{"iden":"sample output 2","content":"No"},{"iden":"sample input 3","content":"FFEE"},{"iden":"sample output 3","content":"Yes"},{"iden":"sample input 4","content":"FREE"},{"iden":"sample output 4","content":"No"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}