**Beautiful Binary String**
Alice has a binary string, B, of length n. She thinks a binary string is beautiful if and only if it doesn't contain the substring “010”.
In one step, Alice can change a 0 to a 1 (or vice-versa). Count and print the minimum number of steps needed to make Alice see the string as beautiful.
Input Format
The first line contains an integer, n (the length of binary string B).
The second line contains a single binary string, B, of length .
Constraint*
1 <= n <= 100
Each character in B E {0, 1}.
Output Format
Print the minimum number of steps needed to make the string beautiful.
Sample Input 0
7
0101010


Sample Output 0
2


Sample Input 1
5
01100


Sample Output 1
0


Sample Input 2
10
0100101010


Sample Output 2
3