#include using namespace std; int main() { int N; int X; cin >> N >> X; vector A(N); for (int i = 0; i < N; i++) { int a; cin >> a; A.at(i) = a; } vector A2; for (int i = 0; i < A.size(); i++) { if (A.at(i) <= X) { A2.emplace_back(A.at(i)); } } int cnt = 0; for (int i = 0; i < A2.size(); i++) { for (int j = i; j < A2.size(); j++) { int sum = A2.at(i) + A2.at(j); if (sum == X && i == j) { cnt += 1; } else if (sum == X and i != j) { cnt += 2; } } } cout << cnt << endl; }