include [HTML_REMOVED]

include [HTML_REMOVED]

include [HTML_REMOVED]

using namespace std;

typedef pair[HTML_REMOVED] PII;

void merge(vector[HTML_REMOVED] &segs)
{
vector[HTML_REMOVED] res;

sort(segs.begin(), segs.end());

int st = -2e9, ed = -2e9;
for (auto seg : segs)
    if (ed < seg.first)
    {
        if (st != -2e9) res.push_back({st, ed});
        st = seg.first, ed = seg.second;
    }
    else ed = max(ed, seg.second);

if (st != -2e9) res.push_back({st, ed});

segs = res;

}

int main()
{
int n;
scanf(“%d”, &n);

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

merge(segs);

cout << segs.size() << endl;

return 0;

}