#include<bits/stdc++.h>
using namespace std;

typedef long long ll;

#define pb push_back
#define ft first
#define sd second
#define all(x) begin((x)), end((x))
#define forn(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define isz(x) (int)(x).size()
/* <-------------------> */

const ll MAX = 2e7;
bool us[(int)MAX];
vector<int> p;

void solve() {
    for (ll i = 2; i < MAX; ++i) if (!us[i]) {
        p.pb((int)i);
        for (ll j = i * i; j < MAX; j += i) {
            us[j] = true;
        }
    }
    int n, m = isz(p), x = 0;
    cin >> n;
    forn (i, m) while (n % p[i] == 0) {
        x ^= i + 1;
        n /= p[i];
    }
    if (n != 1) {
        cout << "David";
    } else {
        cout << (x ? "David" : "Vasya");
    }
}

/* <-------------------> */
// #define LOCAL
int main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
#endif
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    solve();
}