#include <cstdio>
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
/*
问题描述:n个[ai,bi];找k个点使得任意一个区间[ai,bi]总存在某个点t使得ai<=t<=bi
 */
class Interval {
public:
    int a, b;

public:
    Interval(int x, int y) : a(x), b(y) {}
    Interval() {}
    friend bool operator<(const Interval& A, const Interval& B) { return A.b < B.b; }
};
const int maxn = 1e6 + 5;
Interval intervals[maxn];
int main() {
    int n;
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {
        scanf("%d%d", &intervals[i].a, &intervals[i].b);
    }
    sort(intervals + 1, intervals + 1 + n);
    int num = 0;
    int pos = 0;
    for (int i = 1; i <= n; i++) {
        if (pos < intervals[i].a) {
            pos = intervals[i].b;
            num++;
        }
    }
    printf("%d\n", num);
    return 0;
}