func_code_string: #include <bits/stdc++.h>   using namespace std;   const long double PI = 3.1415926535897923846;   const long long int MOD = 1000000007;   const long long int N = 998244353;   long long int power(long long int x, long long int n) {     long long int res = 1;     while (n > 0) {       if (n & 1) res = res * x % MOD;       x = x * x % MOD;       n >>= 1;     }     return res;   }   long long int modinverse(long long int a) { return power(a, MOD - 2); }   void solve() {     long long int n;     cin >> n;     vector<long long int> a(n);     for (long long int i = 0; i < n; i++) {       cin >> a[i];     }     if (n % 2 == 0) {       long long int xo = 0;       for (long long int i = 0; i < n - 1; i++) xo = (xo ^ a[i]);       if (a.back() - xo) {         cout <<  NO n ;         return;       }     }     n -= (1 - n % 2);     cout <<  YES n ;     cout << n - 1 << endl;     for (long long int i = 0; i + 2 < n; i += 2) {       cout << i + 1 <<     << i + 2 <<     << i + 3 << endl;     }     for (long long int i = n - 3; i >= 0; i -= 2) {       cout << i + 1 <<     << i + 2 <<     << i + 3 << endl;     }   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     long long int test = 1;     while (test--) {       solve();     }     cerr <<  Time :   << 1000 * ((double)clock()) / (double)CLOCKS_PER_SEC          <<  ms n ;   }   