美团——交错序列

public class Main8 {
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		while(sc.hasNext()){
			int n=sc.nextInt();
			StringBuffer sb = new StringBuffer();
			for (int i=0;i<n;i++) {
				sb.append(sc.nextInt());
			}
			String s=sb.toString();
			System.out.println(inverseSequence(s));			
		}			
	}
	public static int inverseSequence(String s){
		Stack<Character> stack=new Stack<Character>();
		char[] ch=s.toCharArray();
		stack.push(ch[0]);
		for(int i=1;i<ch.length;i++){
			int popNum=stack.peek();
			if(ch[i]!=popNum){
				stack.push(ch[i]);
			}
		}
		int count=0;
		while(!stack.isEmpty()){
			stack.pop();
			count++;			
		}
		return count;		
	}
}