#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long ll; #define sz size() #define pb push_back #define mp make_pair #define fi first #define se second #define all(c) (c).begin(), (c).end() #define rep(i,a,b) for(ll i=(a);i<(b);++i) #define per(i,a,b) for(ll i=b-1LL;i>=(a);--i) #define clr(a, b) memset((a), (b) ,sizeof(a)) #define ctos(c) string(1,c) #define print(x) cout<<#x<<" = "<>n>>x; map ma1; map ma2; rep(i,0,n){ ll a; cin>>a; ma1[a]++; } ll ans = 0; if(x==0){ map::iterator itr = ma1.begin(); while(itr!=ma1.end()){ ll b = (*itr).se; ans += b*(b-1)/2; itr++; } } else{ map::iterator itr = ma1.begin(); while(itr!=ma1.end()){ ll a = (*itr).fi; ll b = (*itr).se; if(ma2[a]==0){ ans += b*ma1[a^x]; ma2[a]=1; ma2[a^x]=1; } itr++; } } cout << ans << endl; return 0; }