#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; template struct BinaryIndexedTree { int n; vector t; BinaryIndexedTree() {} BinaryIndexedTree(int _n) :n(_n + 1), t(_n + 1) {} void add(int k, Val val) { k++; while (k < n) { t[k] += val; k += (k&-k); } } void set(int k, Val val) { add(k, -sum(k, k + 1)); add(k, val); } Val sum(int k) { Val r = 0; while (k > 0) { r += t[k]; k -= (k&-k); } return r; } Val sum(int l, int r) { return sum(r) - sum(l); } }; void solve() { int N, M; cin >> N >> M; BinaryIndexedTree cnt(M); vector ps; rep(i, N) { int a, b; cin >> a >> b; if (a > b)swap(a, b); ps.emplace_back(a, b); } sort(all(ps)); ll ans = 0; each(p, ps) { ans += cnt.sum(p.first + 1, p.second); cnt.add(p.second, 1); } cout << ans << endl; } int main() { ios::sync_with_stdio(false); cin.tie(0); cout << fixed << setprecision(15); solve(); return 0; }