// includes #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // macros #define ll long long int #define pb emplace_back #define mk make_pair #define pq priority_queue #define FOR(i, a, b) for(int i=(a);i<(b);++i) #define rep(i, n) FOR(i, 0, n) #define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--) #define all(x) (x).begin(),(x).end() #define sz(x) ((int)(x).size()) #define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end()) using namespace std; // types typedef pair P; typedef pair Pl; typedef pair Pll; typedef pair Pd; // constants const int inf = 1e9; const ll linf = 1LL << 50; const double EPS = 1e-10; const int mod = 1e9 + 7; // solve template bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;} template bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;} template struct BIT_{ int n; vector bit; BIT_(int n_){ n = n_; bit = vector(n+1, 0); } void add(int a, T w){ for(int x = a; x < n; x |= (x + 1)){ bit[x] += w; } } T sum(int a){ T res = 0; for(int x = a; x >= 0; x = (x & (x + 1)) - 1){ res += bit[x]; } return res; } }; typedef struct BIT_ BITI; typedef struct BIT_ BITL; int main(int argc, char const* argv[]) { ios_base::sync_with_stdio(false); cin.tie(0); int n, m; cin >> n >> m; vector

vec; vector v(n); rep(i, n){ int x, y; cin >> x >> y; if(x > y)swap(x, y); v[i] = x; vec.pb(mk(x, i)); vec.pb(mk(y, i)); } sort(all(vec)); vector used(n, false); BITI bt(m + 1); ll res = 0; for(int i = 0; i < sz(vec); i++){ int index = vec[i].second; int at = vec[i].first; if(used[index]){ res += bt.sum(at - 1) - bt.sum(v[index]); bt.add(v[index], -1); }else{ bt.add(at, 1); used[index] = true; } } cout << res << endl; return 0; }