#include <cstdio> #include <algorithm> struct abi{int x,y;}a[200005]; int n; long long res; int cmp(abi p, abi q){return p.x<q.x;} int main(){ scanf("%d",&n); for (int i=0; i<n; i++) { scanf("%d %d",&a[i].x,&a[i].y); } std::sort(a,a+n,cmp); int lower,upper; for (int i=0; i<n; i++) { lower=a[i].y; upper=1987654321; for (int j=i+1; j<n; j++) { if(upper>a[j].y && a[j].y>lower){ upper=a[j].y; res++; } } } printf("%lld",res); }