#define _USE_MATH_DEFINES #include "bits/stdc++.h" using namespace std; #define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i)) #define rep(i,j) FOR(i,0,j) #define each(x,y) for(auto &(x):(y)) #define mp make_pair #define MT make_tuple #define all(x) (x).begin(),(x).end() #define debug(x) cout<<#x<<": "<<(x)<; using vi = vector; using vll = vector; const int MAX = 1000005; int N, X, cnt[MAX]; void solve() { cin >> N >> X; ll ans = 0; rep(i, N) { int a; cin >> a; if (X - a >= 0 && X - a < MAX) { ans += cnt[X - a] * 2; } cnt[a]++; if (a * 2 == X)ans++; } cout << ans << endl; } int main() { ios::sync_with_stdio(false); cin.tie(0); cout << fixed << setprecision(15); solve(); return 0; }