#include <iostream>

using namespace std;

int main () {
    int T;
    while (T--) {
        int n;
        cin >> n;
        int ok1 = 0, ok2 = 0;
        for (int i = 1; i <= n; ++i) {
            int x, y;
            cin >> x >> y;
            if (x >= y) {
                ok1 = 1;
            }
            if (x <= y) {
                ok2 = 1;
            }
        }
        cout << ok1 * ok2 ? "Da\n" : "Nu\n";
    }
}