#include <iostream>
#include <vector>
#include <algorithm>

struct section {
    int start;
    int end;
};

bool cmp(const section& s1, const section& s2) {
    return s1.start > s2.start;
}

int main() {
    std::vector<section> sects;
    int n;
    std::cin >> n;
    for (int i = 0; i < n; ++i) {
        section sect;
        std::cin >> sect.start >> sect.end;
        sects.push_back(sect);
    }
    std::sort(sects.begin(), sects.end(), cmp);
    std::vector<section> res;
    section s = sects.back();
    sects.pop_back();

    while (!sects.empty()) {
        section tmp = sects.back();
        sects.pop_back();
        if (tmp.start <= s.end) {
            s.start = tmp.start;
            s.end = std::min(s.end, tmp.end);
        }
        else {
            res.push_back(s);
            s = tmp;
        }
    }

    res.push_back(s);

    std::cout << res.size() << std::endl;
    for (std::vector<section>::iterator it = res.begin(), end = res.end(); it != end; ++it) {
        std::cout << it->start << std::endl;
    }

    return 0;
}