func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long a, b;     cin >> a >> b;     if (a > b || (b - a) % 2) {       cout << -1;       return 0;     }     if (a == b) {       if (a == 0)         cout << 0;       else         cout << 1 <<   n  << a;     } else if (((a + (b - a) / 2) ^ ((b - a) / 2)) == a) {       cout << 2 <<   n  << a + (b - a) / 2 <<     << (b - a) / 2;     } else       cout << 3 << endl << a <<     << (b - a) / 2 <<     << (b - a) / 2;   }   