//header #ifdef LOCAL #include "cxx-prettyprint-master/prettyprint.hpp" #define debug(x) cout << x << endl #else #define debug(...) 42 #endif #pragma GCC optimize("Ofast") #include //types using namespace std; using ll = long long; using ul = unsigned long long; using ld = long double; typedef pair < ll , ll > Pl; typedef pair < int, int > Pi; typedef vector vl; typedef vector vi; template< typename T > using mat = vector< vector< T > >; template< int mod > struct modint { int x; modint() : x(0) {} modint(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {} modint &operator+=(const modint &p) { if((x += p.x) >= mod) x -= mod; return *this; } modint &operator-=(const modint &p) { if((x += mod - p.x) >= mod) x -= mod; return *this; } modint &operator*=(const modint &p) { x = (int) (1LL * x * p.x % mod); return *this; } modint &operator/=(const modint &p) { *this *= p.inverse(); return *this; } modint operator-() const { return modint(-x); } modint operator+(const modint &p) const { return modint(*this) += p; } modint operator-(const modint &p) const { return modint(*this) -= p; } modint operator*(const modint &p) const { return modint(*this) *= p; } modint operator/(const modint &p) const { return modint(*this) /= p; } bool operator==(const modint &p) const { return x == p.x; } bool operator!=(const modint &p) const { return x != p.x; } modint inverse() const { int a = x, b = mod, u = 1, v = 0, t; while(b > 0) { t = a / b; swap(a -= t * b, b); swap(u -= t * v, v); } return modint(u); } modint pow(int64_t n) const { modint ret(1), mul(x); while(n > 0) { if(n & 1) ret *= mul; mul *= mul; n >>= 1; } return ret; } friend ostream &operator<<(ostream &os, const modint &p) { return os << p.x; } friend istream &operator>>(istream &is, modint &a) { int64_t t; is >> t; a = modint< mod >(t); return (is); } static int get_mod() { return mod; } }; //abreviations #define all(x) (x).begin(), (x).end() #define rall(x) (x).rbegin(), (x).rend() #define rep_(i, a_, b_, a, b, ...) for (int i = (a), max_i = (b); i < max_i; i++) #define rep(i, ...) rep_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__) #define rrep_(i, a_, b_, a, b, ...) for (int i = (b-1), min_i = (a); i >= min_i; i--) #define rrep(i, ...) rrep_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__) #define SZ(x) ((int)(x).size()) #define pb(x) push_back(x) #define eb(x) emplace_back(x) #define mp make_pair #define print(x) cout << x << endl #define vsum(x) accumulate(x, 0LL) #define vmax(a) *max_element(all(a)) #define vmin(a) *min_element(all(a)) //functions ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; } ll lcm(ll a, ll b) { return a/gcd(a, b)*b;} templatebool chmax(T &a, const T &b) { if (abool chmin(T &a, const T &b) { if (b T mypow(T x, ll n) { T ret = 1; while(n > 0) { if(n & 1) (ret *= x); (x *= x); n >>= 1; } return ret; } ll modpow(ll x, ll n, const ll mod) { ll ret = 1; while(n > 0) { if(n & 1) (ret *= x); (x *= x); n >>= 1; x%=mod; ret%=mod; } return ret; } uint64_t my_rand(void) { static uint64_t x = 88172645463325252ULL; x = x ^ (x << 13); x = x ^ (x >> 7); return x = x ^ (x << 17); } //graph template template< typename T > struct edge { int src, to; T cost; edge(int to, T cost) : src(-1), to(to), cost(cost) {} edge(int src, int to, T cost) : src(src), to(to), cost(cost) {} edge &operator=(const int &x) { to = x; return *this; } operator int() const { return to; } }; template< typename T > using Edges = vector< edge< T > >; template< typename T > using WeightedGraph = vector< Edges< T > >; using UnWeightedGraph = vector< vector< int > >; //constant #define inf 1000000000005 #define mod 1000000007LL #define endl '\n' typedef modint mint; const long double eps = 0.0001; const long double PI = 3.141592653589793; //library template< typename Monoid > struct SegmentTree { using F = function< Monoid(Monoid, Monoid) >; int sz; vector< Monoid > seg; const F f; const Monoid M1; SegmentTree(int n, const F f, const Monoid &M1) : f(f), M1(M1) { sz = 1; while(sz < n) sz <<= 1; seg.assign(2 * sz, M1); } void set(int k, const Monoid &x) { seg[k + sz] = x; } void build() { for(int k = sz - 1; k > 0; k--) { seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]); } } void update(int k, const Monoid &x) { k += sz; seg[k] = x; while(k >>= 1) { seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]); } } Monoid query(int a, int b) { Monoid L = M1, R = M1; for(a += sz, b += sz; a < b; a >>= 1, b >>= 1) { if(a & 1) L = f(L, seg[a++]); if(b & 1) R = f(seg[--b], R); } return f(L, R); } Monoid operator[](const int &k) const { return seg[k + sz]; } template< typename C > int find_subtree(int a, const C &check, Monoid &M, bool type) { while(a < sz) { Monoid nxt = type ? f(seg[2 * a + type], M) : f(M, seg[2 * a + type]); if(check(nxt)) a = 2 * a + type; else M = nxt, a = 2 * a + 1 - type; } return a - sz; } template< typename C > int find_first(int a, const C &check) { Monoid L = M1; if(a <= 0) { if(check(f(L, seg[1]))) return find_subtree(1, check, L, false); return -1; } int b = sz; for(a += sz, b += sz; a < b; a >>= 1, b >>= 1) { if(a & 1) { Monoid nxt = f(L, seg[a]); if(check(nxt)) return find_subtree(a, check, L, false); L = nxt; ++a; } } return -1; } template< typename C > int find_last(int b, const C &check) { Monoid R = M1; if(b >= sz) { if(check(f(seg[1], R))) return find_subtree(1, check, R, true); return -1; } int a = sz; for(b += sz; a < b; a >>= 1, b >>= 1) { if(b & 1) { Monoid nxt = f(seg[--b], R); if(check(nxt)) return find_subtree(b, check, R, true); R = nxt; } } return -1; } }; int main(){ cin.tie(0); ios::sync_with_stdio(0); cout << setprecision(20); ll n, k; cin>>n>>k; vl a(n); auto f = [](ll a, ll b){return min(a, b);}; SegmentTree seg(n, f, inf); rep(i, n)cin>>a[i], seg.set(i, a[i]); seg.build(); map id, cumsum; rep(i, n)id[a[i]].pb(i); for(auto& p:id){ ll b = p.first; cumsum[b].resize(p.second.size()+1); rep(i, p.second.size()){ cumsum[b][i+1] = cumsum[b][i]+p.second[i]; } } ll ans = 0; rep(i, n){ ll r = k-a[i]; if(id[r].size()==0)continue; ll j = lower_bound(all(id[r]), i)-id[r].begin(); ll ok = j, ng = id[r].size()+1; while(ng-ok>1){ ll mid = (ok+ng)/2; ll m = seg.query(i, id[r][mid-1]+1); if(upper_bound(all(id[m]), id[r][mid-1]) -lower_bound(all(id[m]), i)<=1)ok = mid; else ng = mid; } ans+=cumsum[r][ok]-cumsum[r][j]-(ll)(i-1)*(ok-j); } cout << ans << endl; }