#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long ll; #define FOR(i,a,b) for(ll i=(a);i<(b);++i) #define ALL(v) (v).begin(), (v).end() #define p(s) cout<<(s)< void vprint(T &V){ for(auto v : V){ cout << v << " "; } cout << endl; } int main(){ cin.tie(0); ios::sync_with_stdio(false); // input ll N, X; cin >> N >> X; map mp; FOR(i, 0, N){ ll a; cin >> a; mp[a]++; } ll sum = 0; for(auto p : mp){ ll val = p.first; ll val2 = X - val; sum += mp[val] * mp[val2]; } p(sum); return 0; }