#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, m;
  string s;
  cin >> s;
  int flag1 = 0, f2 = 0, f3 = 0, f4 = 0, f5 = 0;
  if (s.length() >= 5)
    for (int i = 0; i < s.length() - 4; i++)
      if (s[i] == 'D' && s[i + 1] == 'a' && s[i + 2] == 'n' &&
          s[i + 3] == 'i' && s[i + 4] == 'l') {
        flag1++;
      }
  if (s.length() >= 5)
    for (int i = 0; i < s.length() - 4; i++)
      if (s[i] == 'S' && s[i + 1] == 'l' && s[i + 2] == 'a' &&
          s[i + 3] == 'v' && s[i + 4] == 'a') {
        f2++;
      }
  if (s.length() >= 6)
    for (int i = 0; i < s.length() - 5; i++)
      if (s[i] == 'N' && s[i + 1] == 'i' && s[i + 2] == 'k' &&
          s[i + 3] == 'i' && s[i + 4] == 't' && s[i + 5] == 'a') {
        f3++;
      }
  if (s.length() >= 4)
    for (int i = 0; i < s.length() - 3; i++)
      if (s[i] == 'O' && s[i + 1] == 'l' && s[i + 2] == 'y' &&
          s[i + 3] == 'a') {
        f4++;
      }
  if (s.length() >= 3)
    for (int i = 0; i < s.length() - 2; i++)
      if (s[i] == 'A' && s[i + 1] == 'n' && s[i + 2] == 'n') {
        f5++;
      }
  if (flag1 == 1 && f2 == 0 && f3 == 0 && f4 == 0 && f5 == 0) {
    cout << "YES";
  } else if (flag1 == 0 && f2 == 1 && f3 == 0 && f4 == 0 && f5 == 0) {
    cout << "YES";
  } else if (flag1 == 0 && f2 == 0 && f3 == 1 && f4 == 0 && f5 == 0) {
    cout << "YES";
  } else if (flag1 == 0 && f2 == 0 && f3 == 0 && f4 == 1 && f5 == 0) {
    cout << "YES";
  } else if (flag1 == 0 && f2 == 0 && f3 == 0 && f4 == 0 && f5 == 1) {
    cout << "YES";
  } else
    cout << "NO";
  return 0;
}
