Problem Statement

This problem is worth 3 tokens.

Input Format

Your first line of input will contain ~n~. Your next line will contain a string of length ~n~ consisting of only ~0~ and ~1~ characters.

Sample Cases

Input 1

10
1001001001

Output 1

2

Input 2

10
1000101001

Output 2

3

Input 3

10
1110101001

Output 3

5