#include <bits/stdc++.h>
using namespace std;
const long long int MOD = 1e9 + 7;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int t = 1;
  while (t--) {
    long long int n, i, j;
    cin >> n;
    long long int a[n];
    for (i = 0; i < n; i++) cin >> a[i];
    if (n & 1) {
      cout << "YES"
           << "\n"
           << n - 1 << "\n";
      for (i = 1; i < n; i++) {
        cout << '1' << " " << i + 1 << " " << i + 2 << "\n";
        i++;
      }
      for (i = 1; i < n; i++) {
        cout << '1' << " " << i + 1 << " " << i + 2 << "\n";
        i++;
      }
    } else {
      long long int x = a[0];
      for (i = 1; i < n; i++) x ^= a[i];
      if (x != 0) {
        cout << "NO";
      } else {
        cout << "YES"
             << "\n"
             << n - 2 << "\n";
        for (i = 3; i < n + 1; i++) {
          cout << 1 << " " << i << " " << i + 1 << "\n";
          i++;
        }
        for (i = 3; i < n + 1; i++) {
          cout << 1 << " " << i << " " << i + 1 << "\n";
          i++;
        }
      }
    }
  }
  cerr << "Time Taken:" << (float)clock() / CLOCKS_PER_SEC * 1000 << "ms"
       << "\n";
  return 0;
}
