#include <bits/stdc++.h>
using namespace std;
const long long inf = 1e18;
int main() {
  long n;
  cin >> n;
  vector<long long> a(n);
  for (long i = 0; i < n; i++) {
    cin >> a[i];
  }
  if (n % 2 == 1) {
    cout << "YES"
         << "\n";
    cout << (n - 1) << "\n";
    cout << 1 << " " << 2 << " " << 3 << "\n";
    for (long i = 3; i < n; i += 2) {
      cout << 3 << " " << i + 1 << " " << i + 2 << "\n";
    }
    cout << 1 << " " << 2 << " " << 3 << "\n";
    for (long i = 3; i < n; i += 2) {
      cout << 3 << " " << i + 1 << " " << i + 2 << "\n";
    }
  } else {
    long long sum = 0;
    for (long i = 0; i < n; i++) {
      sum = (sum ^ (a[i]));
    }
    if (sum == 0) {
      cout << "YES\n";
      cout << n - 2 << "\n";
      if (n >= 4) {
        cout << "1 2 3\n";
        for (long i = 3; i < n - 1; i += 2) {
          cout << 3 << " " << i + 1 << " " << i + 2 << "\n";
        }
        cout << "1 2 3\n";
        for (long i = 3; i < n - 1; i += 2) {
          cout << 3 << " " << i + 1 << " " << i + 2 << "\n";
        }
      }
    } else {
      cout << "NO\n";
    }
  }
}
