int n, k, tot;

struct _ {int x,r,f;} a[N];

struct __ {

	int type;

	ll x,y;

	bool operator < (const __ & rhs) const {

		if (x!=rhs.x) return x<rhs.x;

		if (y!=rhs.y) return y<rhs.y;

		return type<rhs.type;

	}

} e[N];

ll ans, b[N];

int c[N];

inline void add(int x, int v) {

	for (; x<=*b; x+=x&-x) c[x]+=v;

}

inline int qry(int x) {

	int r = 0;

	for (; x; x^=x&-x) r+=c[x];

	return r;

}

inline void qry(ll x1, ll y1, ll x2, ll y2) {

	e[++tot] = {1,x2,y2};

	e[++tot] = {1,x1-1,y1-1};

	e[++tot] = {2,x1-1,y2};

	e[++tot] = {2,x2,y1-1};

	b[++*b]=y2, b[++*b]=y1-1;

}

inline void ins(int x, int y) {

	e[++tot] = {0,x,y};

}

void merge(int l, int r) {

	if (l==r) return;

	merge(l,mid),merge(mid+1,r);

	int now = l;

	REP(i,mid+1,r) {

		while (now<=mid&&e[now].x<=e[i].x) {

			if (e[now].type==0) add(e[now].y,1);

			++now;

		}

		if (e[i].type==1) ans+=qry(e[i].y);

		else if (e[i].type==2) ans-=qry(e[i].y);

	}

	while (now!=l) {

		if (e[--now].type==0) add(e[now].y,-1);

	}

	inplace_merge(e+l,e+mid+1,e+r+1);

}

int main() {

	REP(i,1,n) {

//		qry();

//		ins();

	}

	sort(b+1,b+1+*b),*b=unique(b+1,b+1+*b)-b-1;

	REP(i,1,tot) e[i].y=lower_bound(b+1,b+1+*b,e[i].y)-b;

	merge(1,tot);

	printf("%lld\n", ans);

}