#include <fstream>
#include <vector>
using namespace std;
ifstream cin("conex.in");
ofstream cout("conex.out");
const int DIM = 101;
int a[DIM][DIM], q[DIM], viz[DIM], t[DIM];
void bfs(int x, int nc);
int n;
int main()
{
    int m, k;
    cin >> n;
    int x, y;
    while(cin >> x >> y)
    {
        a[x][y] = a[y][x] = 1;
    }
    int conex = 0;
    bfs(1, conex + 1);
    return 0;
}

void bfs(int k, int nc)
{
    int st, dr, nod;
    st = dr = 0;
    q[st] = k;
    viz[k] = nc;
    while(st <= dr)
    {
        nod = q[st++];
        for(int i = 1; i <= n; ++i)
        {
            if(a[nod][i])
            {
                if(!viz[i])
                {
                    q[++dr] = i;
                    viz[i] = nc;
                    t[i] = nod;
                }
            }
        }
    }
    if(n == dr + 1)
        cout << "DA";
    else
        cout << "NU";
}