#include #include using namespace std; #define rep(i, n) for (int i = 0; i < (int)(n); i++) #define all(x) (x).begin(), (x).end() #define ll long long #define ld long double #define INF 1000000000000000000 typedef pair pll; typedef pair pint; int main() { cin.tie(0); ios::sync_with_stdio(false); int N, X; cin >> N >> X; vector A(N); map ma; rep(i, N) { cin >> A[i]; ma[A[i]]++; } ll ans = 0; rep(i, N) { ll a = X - A[i]; ans += ma[a]; } cout << ans << endl; }