#include using namespace std; #define rep(i, n) for (int i = 0; i < (int)(n); ++i) int N, X, a[1 << 17]; long long ans = 0, cnt[1 << 17]; signed main() { cin.tie(0)->sync_with_stdio(0); cin >> N >> X; rep(i, N) { cin >> a[i]; ++cnt[a[i]]; } if (X == 0) { ans = cnt[0] * (cnt[0] + 1) / 2; cout << ans << endl; return 0; } rep(i, N) { if (a[i] + a[i] == X) ++ans; else if (0 <= X - a[i] && X - a[i] < 1 << 17) ans += cnt[X - a[i]]; } cout << ans << endl; }