#include <iostream>
#include <vector>
#include <cstring>
#include <algorithm>
#include <map>
using namespace std;
typedef long long ll;

int main()
{
    int n;
    cin >> n;
    int niza[n];
    for(int i = 0; i < n; i++) {
        cin >> niza[i];
    }
    int x;
    cin >> x;

    int L = 0;
    int R = n - 1;
    while(L <= R) {
        int middle = (L + R) / 2;
        if(niza[middle] == x) {
            cout << "DA" << endl;
            break;
        }
        if(niza[middle] < x) {
            L = middle + 1;
        }
        else {
            R = middle - 1;
        }
    }
    return 0;
}

/*


 **/