题目描述
Currently, XXOC's rap is a string consisting of zeroes, ones, and question marks. Unfortunately, haters gonna hate. They will write $x$ angry comments for every occurrence of subsequence 01 and $y$ angry comments for every occurrence of subsequence 10. You should replace all the question marks with 0 or 1 in such a way that the number of angry comments would be as small as possible.
String $b$ is a subsequence of string $a$, if it can be obtained by removing some characters from $a$. Two occurrences of a subsequence are considered distinct if sets of positions of remaining characters are distinct.
Input
The first line contains string $s$ — XXOC's rap ($1 \le |s| \leq 10^5$). The second line contains two integers $x$ and $y$ — the number of angry comments XXOC will recieve for every occurrence of 01 and 10 accordingly ($0 \leq x, y \leq 10^6$).
Output
Output a single integer — the minimum number of angry comments.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
样例输出
提示
In the first example one of the optimum ways to replace is 001. Then there will be $2$ subsequences 01 and $0$ subsequences 10. Total number of angry comments will be equal to $2 \cdot 2 + 0 \cdot 3 = 4$.
In the second example one of the optimum ways to replace is 11111. Then there will be $0$ subsequences 01 and $0$ subsequences 10. Total number of angry comments will be equal to $0 \cdot 13 + 0 \cdot 37 = 0$.
In the third example one of the optimum ways to replace is 1100. Then there will be $0$ subsequences 01 and $4$ subsequences 10. Total number of angry comments will be equal to $0 \cdot 239 + 4 \cdot 7 = 28$.
In the fourth example one of the optimum ways to replace is 01101001. Then there will be $8$ subsequences 01 and $8$ subsequences 10. Total number of angry comments will be equal to $8 \cdot 5 + 8 \cdot 7 = 96$.