#include <stdio.h>
#include <algorithm>
using namespace std;

const int maxs = 300;
int c,g[1010][maxs*2+1],l[1010],s[1010],p[1010],r[100010];

void just()
{
	int n = 0;
	for (int i=0;i<c;i++){
		for (int j=0;j<s[i];j++){
			r[n++] = g[i][j] + p[i];
		}
	}

	c = (n + maxs - 1) / maxs;
	for (int i=0;i<c;i++) s[i] = p[i] = 0;
	for (int i=0;i<n;i++){
		int u = i/maxs, e = i%maxs;
		g[u][e] = r[i];
		l[u] = r[i];
		s[u]++;
	}
}

void del(int i, int v)
{
	s[i]--;
	for (int j=v;j<s[i];j++) g[i][j] = g[i][j+1];
}

void rem(int y)
{
	int i = lower_bound(l, l + c, y) - l;
	if (i < c){
		int v = lower_bound(g[i], g[i] + s[i], y - p[i]) - g[i];
		del(i, v);
		if (s[i] == 0) just();
		else if (s[i] == v) l[i] = g[i][v-1];
	}
}

void add(int x, int y)
{
	int u = lower_bound(l, l + c, x) - l;
	for (int i=u;i<c;i++){
		int a = g[i][0] + p[i];
		int b = g[i][s[i]-1] + p[i];
		if (x <= a && b <= y) p[i]++, l[i]++;
		else if (max(x, a) <= min(b, y)){
			for (int v=0;v<s[i];v++){
				int &w = g[i][v];
				w += p[i];
				if (x <= w && w <= y) w++;
				l[i] = w;
			}
			p[i] = 0;
		}
		else break;
	}
}

void mak(int i, int v)
{
	for (int j=s[i];j>v;j--) g[i][j] = g[i][j-1];
	s[i]++;
}

void ins(int x)
{
	if (c == 0){
		g[0][0] = l[0] = x; s[0] = 1; p[0] = 0; c = 1;
		return;
	}

	int i = lower_bound(l, l + c, x) - l;
	if (i == c) i--;
	x -= p[i];
	int v = lower_bound(g[i], g[i] + s[i], x) - g[i];
	mak(i, v);
	g[i][v] = x;
	if (s[i] == maxs * 2) just();
	else if (s[i] == v + 1) l[i] = x + p[i];
}

int main()
{
	int N; scanf ("%d",&N); while (N--){
		int x,y; scanf ("%d %d",&x,&y);
		rem(y);
		add(x,y);
		ins(x);
	}

	int ans = 0;
	for (int i=0;i<c;i++) ans += s[i];
	printf ("%d\n",ans);

	return 0;
}