#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> PII;

vector<PII> segs;
int n;

const int inf = 2e9;
vector<PII> rev;

void merge() {

    int st = -inf, ed = -inf;
    sort(segs.begin(), segs.end());
    for (auto seg : segs) {
        if (ed < seg.first) { // 新区间
            if (st != -inf) rev.push_back({st, ed});
            st = seg.first, ed = seg.second;
        } 
        else ed = max(ed, seg.second);
    }

    if (st != -inf) rev.push_back({st, ed});

    segs = rev;

}

int main(void) {
    scanf("%d", &n);
    for (int i = 0; i < n; ++i) {
        int l, r;
        scanf("%d%d", &l, &r);
        segs.push_back({l, r});
    }

    merge();

    printf("%d", segs.size());

    return 0;

}