{"raw_statement":[{"iden":"problem statement","content":"Takahashi has an empty string $S$ and a variable $x$ whose initial value is $0$.\nAlso, we have a string $T$ consisting of `0` and `1`.\nNow, Takahashi will do the operation with the following two steps $|T|$ times.\n\n*   Insert a `0` or a `1` at any position of $S$ of his choice.\n*   Then, increment $x$ by the sum of the digits in the odd positions (first, third, fifth, ...) of $S$. For example, if $S$ is `01101`, the digits in the odd positions are `0`, `1`, `1` from left to right, so $x$ is incremented by $2$.\n\nPrint the maximum possible final value of $x$ in a sequence of operations such that $S$ equals $T$ in the end."},{"iden":"constraints","content":"*   $1 \\leq |T| \\leq 2 \\times 10^5$\n*   $T$ consists of `0` and `1`."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$T$"},{"iden":"sample input 1","content":"1101"},{"iden":"sample output 1","content":"5\n\nBelow is one sequence of operations that maximizes the final value of $x$ to $5$.\n\n*   Insert a `1` at the beginning of $S$. $S$ becomes `1`, and $x$ is incremented by $1$.\n*   Insert a `0` to the immediate right of the first character of $S$. $S$ becomes `10`, and $x$ is incremented by $1$.\n*   Insert a `1` to the immediate right of the second character of $S$. $S$ becomes `101`, and $x$ is incremented by $2$.\n*   Insert a `1` at the beginning of $S$. $S$ becomes `1101`, and $x$ is incremented by $1$."},{"iden":"sample input 2","content":"0111101101"},{"iden":"sample output 2","content":"26"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}