{"raw_statement":[{"iden":"problem statement","content":"$N$ tiles are arranged in a row from left to right. The initial color of each tile is represented by a string $S$ of length $N$.\nThe $i$\\-th tile from the left is painted black if the $i$\\-th character of $S$ is `0`, and painted white if that character is `1`.\nYou want to repaint some of the tiles black or white, so that any two adjacent tiles have different colors.\nAt least how many tiles need to be repainted to satisfy the condition?"},{"iden":"constraints","content":"*   $1 \\leq |S| \\leq 10^5$\n*   $S_i$ is `0` or `1`."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$S$"},{"iden":"sample input 1","content":"000"},{"iden":"sample output 1","content":"1\n\nThe condition can be satisfied by repainting the middle tile white."},{"iden":"sample input 2","content":"10010010"},{"iden":"sample output 2","content":"3"},{"iden":"sample input 3","content":"0"},{"iden":"sample output 3","content":"0"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}