#include using namespace std; typedef long long ll; typedef pair p_ll; template void debug(T itr1, T itr2) { auto now = itr1; while(now=0; i--) #define popcount __builtin_popcount const ll LLINF = (1ll<<61)-1; const ll INF = pow(2,30)-1; ll gcd(ll a, ll b) { if (a> N >> X; vector A(N); rep(i,N) cin >> A[i]; sort(all(A), comp); // debug(all(A)); bool ok = true; rep(i,N-1) ok &= A[i]<(A[i+1]^X) && (A[i]^X)