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Description

Game U-turn is a card game of patience, played by a single player. Given a sequence
of cards with some cards face up and others face down at arbitrary positions, a player is
required to perform a series of operation called U-turn to make all cards face up without
altering positions of cards in the sequence. A U-turn operation is performed on a sub-string of
cards of any length to u-turn the face of each card in the sub-string, i.e., if the face of a card is
up then put it down and if it is down then put it up, without altering positions of cards in the
sub-string. The effort of a U-turn operation is the length of the sub-string on which the
operation is performed. The series of U-turns should be such that the effort of each U-turn
operation is distinct and the total effort of the series of operations is minimum.


Write a program to find the total minimum effort required to make all cards of a given
sequence face up using a series of U-turn operation. Assume that the sequence of cards is
represented by a string of 0’s and 1’s where a zero represents a card with face up and a one
represents a card with face down.

Input Format

Input may contain multiple test cases.

Each test case has a single input line containing a string of 0’s and 1’s. The length of the string is fifteen or less.


Input terminates with a line containing 0 as the input for a test case.

Output Format

For each test case, print the total minimum effort required.

Sample Input 1

1000101 
001100010 
1010100000 
0

Sample Output 1

9
3
7

Hints

Problem Source

Migrated from old NTUJ.

ICPC Kanpur, 2008

Subtasks

No. Testdata Range Score

Testdata and Limits

No. Time Limit (ms) Memory Limit (VSS, KiB) Output Limit (KiB) Subtasks
0 10000 65536 200