#include <cstdio>
#include <algorithm>
using namespace std;
typedef long long ll;
const int MAX = 200020;
struct point {
int x, y;
bool operator < (const point &t) const {
return x < t.x;
}
};
int n;
point data[MAX], tmp[MAX];
void init(){
scanf("%d", &n);
int i;
for(i = 0; i<n; i++)
scanf("%d%d", &data[i].x, &data[i].y);
sort(data, data+n);
}
point lStack[MAX], rStack[MAX];
int lTop, rTop;
ll solve(int s, int e){
if(s >= e-1)
return 0;
int m = (s+e)>>1;
ll ans = 0;
ans += solve(s, m);
ans += solve(m, e);
lTop = rTop = 0;
int r, l = s;
for(r = m; r<e; r++){
while(l < m && data[l].y < data[r].y){
while(lTop && lStack[lTop-1].x < data[l].x)
lTop--;
lStack[lTop++] = data[l++];
}
int minY;
while(rTop && rStack[rTop-1].x > data[r].x)
rTop--;
minY = rTop ? rStack[rTop-1].y : -1;
rStack[rTop++] = data[r];
int p = 0, q = lTop, r;
while(p < q){
r = (p+q) >> 1;
if(lStack[r].y > minY)
q = r;
else
p = r+1;
}
ans += lTop-p;
}
int tFull = 0;
l = s;
r = m;
while(1){
if(l == m && r == e)
break;
if((l < m && data[l].y < data[r].y) || r == e)
tmp[tFull++] = data[l++];
else
tmp[tFull++] = data[r++];
}
int i;
for(i = 0; i<tFull; i++)
data[s+i] = tmp[i];
return ans;
}
int main(){
init();
printf("%lld\n", solve(0, n));
return 0;
}
