/**
 * Patryk Kisielewski
 * 
 * Potyczki Algorytmiczne 2025
 * Zadanie: SZK - Szkoła [C]
*/
#include <algorithm>
#include <iostream>
#include <queue>
#include <vector>

using namespace std;

int main() {
    long long n, m, s;

    cin >> n >> m >> s;

    vector<pair<long long, long long>> v(m), v2;
    for (auto& p : v) {
        cin >> p.first >> p.second;
    }
    v.push_back({0,0});
    v.push_back({n+1,n+1});
    sort(v.begin(), v.end());
    for (unsigned i = 1; i < v.size(); ++i) {
        if (v[i-1].second + 1 < v[i].first) {
            v2.push_back({v[i-1].second + 1, v[i].first - 1});
        }
    }
    long long pos1 = 0;
    while (v2[pos1].second <= s) {
        ++pos1;
    }
    long long pos2 = v2.size() - 1;
    while (s < v2[pos2].first + 1) --pos2;
    if (pos1 == pos2) {
        cout << s - 1 << endl;
        return 0;
    }
    long long f1 = v2[pos1].first;
    long long f2 = v2[pos2].second;
    if (f1 - s < s - f2) {
        cout << f1 << endl;
        return 0;
    } else {
        cout << f2 << endl;
        return 0;
    }

    return 0;
}