#include using namespace std; #define REP(i,a,n) for(int i=(a); i<(int)(n); i++) #define rep(i,n) REP(i,0,n) #define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it) #define ALLOF(c) (c).begin(), (c).end() typedef long long ll; typedef unsigned long long ull; int main(){ int N, X; cin >> N >> X; map A; rep(i,N){ int a; cin >> a; A[a]++; } ll ret = 0; FOR(it,A){ int ai = it->first; int aj = X - ai; if(aj < 0) continue; ret += A[ai] * (ll)A[aj]; } cout << ret << endl; return 0; }