func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2e5 + 5;   vector<int> basis;   void add(int x) {     for (int& a : basis)       if (a & -a & x) x ^= a;     if (x == 0) return;     for (int& a : basis)       if (x & -x & a) a ^= x;     basis.emplace_back(x);   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     int x = 0;     int n;     cin >> n;     for (int i = 1; i <= n; ++i) {       int a;       cin >> a;       add(x ^= a);     }     if (x)       cout << basis.size();     else       cout <<  -1 ;   }   