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

int main() {
    int64_t n, s;
    int32_t m;
    std::cin >> n >> m >> s;

    std::vector<std::pair<int64_t, int64_t>> ll, rr;
    int64_t sl, sr;
    for (int32_t i = 0; i < m; ++i) {
        int64_t l, r;
        std::cin >> l >> r;

        if (r < s) {
            ll.emplace_back(l, r);
        } else if (l > s) {
            rr.emplace_back(l, r);
        } else {
            sl = l - 1;
            sr = r + 1;
        }
    }

    std::sort(ll.begin(), ll.end(), [](auto l, auto r) { return l.first > r.first; });
    for (auto lll: ll) {
        if (lll.second < sl) {
            break;
        }
        sl = lll.first - 1;
    }

    std::sort(rr.begin(), rr.end(), [](auto l, auto r) { return l.first < r.first; });
    for (auto rrr: rr) {
        if (rrr.first > sr) {
            break;
        }
        sr = rrr.second + 1;
    }

    if (sl <= 0) {
        std::cout << sr << "\n";
    } else if (sr > n) {
        std::cout << sl << "\n";
    } else if (s - sl > sr - s) {
        std::cout << sr << "\n";
    } else {
        std::cout << sl << "\n";
    }
}