//#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

ifstream cin("conex.in");
ofstream cout("conex.out");
const int kSize = 100000;
int viz[kSize];
vector<vector<int>> g;


void DFS(int nod)
{
    viz[nod] = 1;
    //cout << q << ' ';
    for (int i = 0; i < g[nod].size(); i += 1)
        if( !viz[g[nod][i]]){
            DFS(g[nod][i]);
    }
}
int main()
{
    int m, n, comp = 0;
    cin >> n;
    g = vector<vector<int>> (n);
    int x, y;
    while(cin >> x >> y){
        x -= 1; y -= 1;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    for(int i = 0; i < n; i++)
        if(viz[i] == 0){
            DFS(i);
            comp++;
    }
    if(comp == 1 )
        cout << "DA";
    else
        cout << "NU";
    return 0;
}