#include <iostream>#include <cstring>#include <cctype>#include <cstdlib>#include <cmath>#include <vector>#include <cstdio>#include <set>#include <map>#include <algorithm>#define N 100005typedef long long LL;#define fi first#define se secondusing namespace std;int n , m;pair<int , int> a[N];int top[N] , bot[N] , d[N] , c[N];struct opt{ int p , x; bool f; bool operator < (const opt& r) const { if (x == r.x) return f > r.f; return x < r.x; }}t[N << 1];void add(int x , int w){ for (int i = x ; i <= m ; i += i & -i) c[i] += w;}int sum(int x){ int _s = 0; for (int i = x ; i ; i &= i - 1) _s += c[i]; return _s;}void work(){ int i , j , x , y; scanf("%d",&n); for (i = 1 ; i <= n ; ++ i) scanf("%d%d",&a[i].fi , &a[i].se) , d[i] = a[i].se; sort(a + 1 , a + 1 + n) , sort(d + 1 , d + 1 + n); m = unique(d + 1 , d + 1 + n) - d - 1; for (i = 1 ; i <= n ; ++ i) a[i].se = lower_bound(d + 1 , d + 1 + m , a[i].se) - d; for (i = 1 ; i <= m ; ++ i) top[i] = 1 << 30; for (i = 1 ; i <= n ; ++ i) { if (top[a[i].se] == 1 << 30) top[a[i].se] = a[i].fi; bot[a[i].se] = a[i].fi; } for (i = 1 ; i <= m ; ++ i) t[2 * i - 1] = (opt) {i , top[i] , 1} , t[2 * i] = (opt) {i , bot[i] , 0}; sort(t + 1 , t + m + m + 1); LL ans = 0; j = 1; for (i = 1 ; i <= n ; ) { x = a[i].fi; int l = 1 << 30 , r = -1 << 30; while (i <= n && a[i].fi == x) l = min(a[i].se , l) , r = max(a[i].se , r) , ++ i; while (j <= m + m && t[j].x < x) ++ j; while (j <= m + m && t[j].x == x && t[j].f) add(t[j].p , 1) , ++ j; ans += sum(r) - sum(l -1); while (j <= m + m && t[j].x == x && !t[j].f) add(t[j].p , -1) , ++ j; } cout << ans << endl;}int main(){ work(); return 0;}
