#include <bits/stdc++.h>

using namespace std;

char buf[(1<<21)+5],*p1,*p2;
#define getchar() (p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?EOF:*p1++)

inline int read() {
	int x = 0, f = 0; char ch = getchar();
	while (!isdigit(ch)) f |= (ch == '-'), ch = getchar();
	while (isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
	return f ? -x : x;
}

const int N = 1e5 + 500, unit = 330;

int m, s, b[N];

deque<int> q[unit]; int add[unit];

int& pos(int x) { return q[b[x]][x % unit]; }
int val(int x) { return q[b[x]][x % unit] + add[b[x]]; }

signed main() {
	// freopen("a.in", "r", stdin);
	// freopen("a.out", "w", stdout);
	for (int s = 0; s <= 1e5; s += unit) { 
		m = s / unit, q[m].assign(unit, 0);
		for (int i = s; i < s + unit; ++i) b[i] = m;
	}
	int T = read(); while (T--) {
		int l = read(), r = read();
		if (b[l] == b[r]) {
			for (int i = r; i > l; --i) pos(i) = pos(i - 1) + 1;
			pos(l) = val(l - 1) + 1 - add[b[l]];
		} else {	
			for (int i = r; i > b[r] * unit; --i) pos(i) = pos(i - 1) + 1; 
			pos(b[r] * unit) = val(b[r] * unit - 1) + 1 - add[b[r]];
			for (int i = b[r] - 1; i > b[l]; --i) {
				q[i].push_front(val(i * unit - 1) - add[i]);
				q[i].pop_back(), ++add[i];
			}
			for (int i = (b[l] + 1) * unit - 1; i > l; --i) pos(i) = pos(i - 1) + 1;
			pos(l) = val(l - 1) + 1 - add[b[l]];
		}
		for (int i = r + 1; i < (b[r] + 1) * unit; ++i) 
			if (val(i) < val(r)) pos(i) = val(r) - add[b[i]];	
		for (int i = b[r] + 1; i <= m; ++i) {
			if (val((i + 1) * unit - 1) < val(r)) { ++add[i]; continue; }
			for (int j = i * unit; j < (i + 1) * unit; ++j)
				if (val(j) < val(r)) pos(j) = val(r) - add[i];	break;
		}
	}
	cout << val((m + 1) * unit - 1);
	return 0;
}