#include<iostream>
using namespace std;

int main()
{
    int noOfElements;
    cout << "Introduceti numarul de elemente: ";
    cin >> noOfElements;
    int *elements = new int[noOfElements];

    cout << "Introduceti elementele array-ului (doar 0 si 1) : " << endl;
    for (int i = 0; i < noOfElements; i++)
    {
        cout << "elements[" << i << "]= ";
        cin >> elements[i];
    }

    int no = 0;

    for (int i = 0; i < noOfElements; i++)
    {
        if (elements[i] == 1)
        {
            if (elements[i - 1] == 0 || elements[i + 1] == 0)
            {
                continue;
            }
            else
            {
                no++;
            }
        }
    }

    if (no == 0)
    {
        cout << "Da" << endl;
    }
    else
    {
        cout << "No" << endl;
    }

    delete[] elements;
}