code_contests-0181/instruction.md

p02652 AtCoder Grand Contest 045 - 01 Unbalanced

Problem Description

Given is a string S, where each character is 0, 1, or ?.

Consider making a string S' by replacing each occurrence of ? with 0 or 1 (we can choose the character for each ? independently). Let us define the unbalancedness of S' as follows:

• (The unbalancedness of S') = \max \{ The absolute difference between the number of occurrences of 0 and 1 between the l-th and r-th character of S (inclusive) :\ 1 \leq l \leq r \leq |S|\}

Find the minimum possible unbalancedness of S'.

Constraints

• 1 \leq |S| \leq 10^6
• Each character of S is 0, 1, or ?.

Input

Input is given from Standard Input in the following format:

S

Output

Print the minimum possible unbalancedness of S'.

Examples

Input

0??

Output

1

Input

0??0

Output

2

Input

??00????0??0????0?0??00??1???11?1?1???1?11?111???1

Output

4

Contest Information

• Contest ID: 0
• Problem Index:
• Points: 0.0
• Rating: 0
• Tags:
• Time Limit: {'seconds': 2, 'nanos': 0} seconds
• Memory Limit: 1073741824 bytes

Task

Solve this competitive programming problem. Provide a complete solution that handles all the given constraints and edge cases.