#include<iostream>
using namespace std;
int main()
{
    int n, g = 0, cnt1 =1, cnt2=1;
    cin >> n;
    while(n != 0)
    {
        if(n == 1) cnt2 = 1, cnt1 = 1;

        if(n == 2)
        {
            if(cnt1 == 1)
            {
                cnt2 = 2, cnt1 = 2;
            }
            else if(cnt1 == 2) cnt2 += 2;
        }

        g += cnt2;
        cin >> n;

    }

    cout << g << endl;
    return 0;
}