#include<iostream>
#include<algorithm>
#include<vector>
#include<set>
#define FI first
#define SE second
#define PB push_back
#define MP make_pair
using namespace std;
typedef long long LL;
typedef pair<LL,LL>PL;
typedef vector<LL>VL;
typedef set<LL>SL;
const LL INF=1LL<<55LL;
struct SCW
{
LL x,y;
}x[234567],y[234567],P[234567];
bool cmp1(SCW X,SCW Y)
{
return X.x<Y.x;
}
bool cmp2(SCW X,SCW Y)
{
return X.x>Y.x;
}
bool cmp3(SCW X,SCW Y)
{
return X.y<Y.y;
}
SCW min(SCW X,SCW Y)
{
if(X.x>Y.x)
return Y;
return X;
}
LL N,N2,C,s,i;
SCW xmi;
vector<SCW>seg[876543];
void SUM(LL N,LL x1,LL x2,LL X1,LL X2)
{
if(x1>x2||X1>X2||x1>X2||x2<X1)
return;
if(X1>=x1&&X2<=x2)
{
if(!seg[N].empty())
{
vector<SCW>::iterator it=upper_bound(seg[N].begin(),seg[N].end(),xmi,cmp2);
xmi=min(xmi,seg[N].back());
s+=seg[N].end()-it;
}
return;
}
LL mid=X1+X2>>1;
SUM(N<<1,x1,x2,X1,mid);
SUM((N<<1)+1,x1,x2,mid+1,X2);
return;
}
void IN(LL N,SCW X)
{
if(!seg[N].empty())
seg[N].erase(upper_bound(seg[N].begin(),seg[N].end(),X,cmp3),seg[N].end());
seg[N].PB(X);
if(N<2)
return;
IN(N>>1,X);
return;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin>>N;
for(N2=1;N2<N;N2<<=1);
for(i=0;i<N;i++)
{
cin>>x[i].x>>y[i].x;
x[i].y=y[i].y=i;
}
sort(x,x+N,cmp1);
sort(y,y+N,cmp1);
C=0;
P[x[0].y].x=0;
for(i=1;i<N;i++)
P[x[i].y].x=++C;
C=0;
P[y[0].y].y=0;
for(i=1;i<N;i++)
P[y[i].y].y=++C;
sort(P,P+N,cmp1);
for(i=N;i-->0;)
{
xmi.x=xmi.y=INF;
SUM(1,P[i].y+1,N2-1,0,N2-1);
IN(N2+P[i].y,P[i]);
}
cout<<s<<endl;
return 0;
}
