#include using namespace std; #define ALL(x) x.begin(),x.end() #define rep(i,n) for(int i=0;i<(n);i++) #define debug(v) cout<<#v<<":";for(auto x:v){cout<bool chmax(T &a,const T &b){if(abool chmin(T &a,const T &b){if(b ostream &operator<<(ostream &os,const pair&p){ os< ostream &operator<<(ostream &os,const vector&v){ for(int i=0;i<(int)v.size();i++) os< struct SegmentTree{ using F=function; int sz; vector seg; const F f; const Monoid gen; SegmentTree(int n,const F f,const Monoid &gen):f(f),gen(gen){ sz=1; while(sz0;k--) seg[k]=f(seg[2*k],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],seg[2*k+1]); } // [a,b) Monoid query(int a,int b){ Monoid L=gen,R=gen; for(a+=sz,b+=sz;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]; } }; ll f(ll a,ll b){return a+b;} signed main(){ int n,m;cin>>n>>m; vector> v; int l[n]; rep(i,n){ int a,b;cin>>a>>b; if(a>b) swap(a,b); v.push_back({a,(i+1)}); v.push_back({b,-(i+1)}); l[i]=a; } sort(ALL(v)); SegmentTree seg(m,f,0); seg.build(); ll ans=0; for(auto p:v){ int idx=abs(p.second)-1; if(p.second<0){ seg.update(l[idx],0); ans+=seg.query(l[idx],p.first); }else{ seg.update(p.first,1); } } cout<