A13684. Grime Zoo

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.

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 a single integer — the minimum number of angry comments.

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 $8 \cdot 5 + 8 \cdot 7 = 96$ .