#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include template inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; } //constexpr long long MAX = 5100000; constexpr long long INF = 1LL << 60; constexpr int inf = 1000000007; constexpr long long mod = 1000000007LL; //constexpr long long mod = 998244353LL; const long double PI = acos((long double)(-1)); using namespace std; typedef unsigned long long ull; typedef long long ll; typedef long double ld; template struct BIT { int n; vector bit; BIT() :n(0) {} BIT(int _n) :n(_n) { bit = vector(n + 1); } void add1(int idx, T val) { for (int i = idx; i <= n; i += i & -i) bit[i] += val; } T sum1(int idx) { T res = 0; for (int i = idx; i > 0; i -= i & -i) res += bit[i]; return res; } //0-indexed void add(int idx, T val) { add1(idx + 1, val); } //0-indexed [left, right) T sum(int left, int right) { return sum1(right) - sum1(left); } int lower_bound(T x) { int res = 0; int k = 1; while (2 * k <= n) k <<= 1; for (; k > 0; k >>= 1) { if (res + k <= n and bit[res + k] < x) { x -= bit[res + k]; res += k; } } return res; } }; int main() { /* cin.tie(nullptr); ios::sync_with_stdio(false); */ int n, m; scanf("%d %d", &n, &m); vector> vp(n); for (int i = 0; i < n; i++) { int a, b; scanf("%d %d", &a, &b); if (a > b) swap(a, b); vp[i] = { a,b }; } sort(vp.begin(), vp.end()); ll res = 0; BIT bit(m); for (int i = 0; i < n; i++) { res += bit.sum(vp[i].first, vp[i].second); bit.add(vp[i].second, 1); } cout << res << endl; return 0; }