#include #define rep(i,a,b) for(int i=a;i=b;i--) #define fore(i,a) for(auto &i:a) #define all(x) (x).begin(),(x).end() #pragma GCC optimize ("-O3") using namespace std; void _main(); int main() { cin.tie(0); ios::sync_with_stdio(false); _main(); } typedef long long ll; const int inf = INT_MAX / 2; const ll infl = 1LL << 60; templatebool chmax(T &a, const T &b) { if (abool chmin(T &a, const T &b) { if (b> N >> X; rep(i, 0, N) cin >> A[i]; rep(i, 0, N) cnt[A[i]]++; ll ans = 0; rep(i, 0, N) { int d = X - A[i]; if (0 <= d and d <= 100000) ans += cnt[d]; } cout << ans << endl; }