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#include <bits/stdc++.h>

using namespace std;


int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    long long n, m, s;

    cin >> n >> m >> s;

    vector<pair<long long, long long>> ranges;

    for (int i = 0; i < m; i++) {
        long long a, b;

        cin >> a >> b;

        ranges.push_back(pair(a, b));
    }


    sort(ranges.begin(), ranges.end(), [](pair<long long, long long> a, pair<long long, long long> b) {
        return a.second < b.first;
    });

    long long res = 3*n;

    // for (auto r : ranges) {
        // cout << r.first << " " << r.second << endl;
    // }

    if (ranges[0].first > 1) {
        res = ranges[0].first - 1;
    }

    for (int i = 1; i < ranges.size(); i++) {
        // cout << ranges[i].first << " " << ranges[i].second << " " << res << endl;

        if (ranges[i].first - ranges[i - 1].second == 1) continue;

        // cout << abs(ranges[i].first - 1 - s) << " " << abs(res - s) << endl;
        // cout << abs(ranges[i - 1].second + 1 - s) << " " << abs(res - s) << endl;
        // if (ranges[i].first < s) {
            if (abs(ranges[i].first - 1 - s) < abs(res - s)) {
                res = ranges[i].first - 1;
            }
        // } else {
            if (abs(ranges[i - 1].second + 1 - s) < abs(res - s)) {
                res = ranges[i - 1].second + 1;
            }
        // } 
    }
    // cout << res << endl;
    if (ranges[ranges.size() - 1].second < n) {
        if (abs(ranges[ranges.size() - 1].second + 1 - s) < abs(res - s)) {
            res = ranges[ranges.size() - 1].second + 1;
        }
    }

    cout << res << endl;
   
    return 0;
}