CCF-201803-1-跳一跳

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        List<Integer> arr = new ArrayList<Integer>();
        int num;
        while (in.hasNext()) {
            num = in.nextInt();
            arr.add(num);
            if (num == 0) {
                in.close();
                break;
            }
        }
        int count = 0;
        int grade = 0;
        for (int i = 0; i < arr.size(); i++) {
            if (arr.get(i) == 1) {
                count = 0;
                grade += 1;
            } else if (arr.get(i) == 2) {
                count += 2;
                grade += count;
            } else {
                break;
            }
        }
        System.out.println(grade);
    }
}