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#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>
using namespace std;

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

    vector<pair<long long, long long>> intervals(m);
    for (int i = 0; i < m; ++i) {
        cin >> intervals[i].first >> intervals[i].second;
    }

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

    vector<pair<long long, long long>> free_intervals;

    if (intervals[0].first > 1) {
        free_intervals.emplace_back(1, intervals[0].first - 1);
    }

    for (int i = 1; i < m; ++i) {
        long long prev_end = intervals[i-1].second;
        long long curr_start = intervals[i].first;
        if (prev_end + 1 <= curr_start - 1) {
            free_intervals.emplace_back(prev_end + 1, curr_start - 1);
        }
    }

    if (intervals.back().second < n) {
        free_intervals.emplace_back(intervals.back().second + 1, n);
    }

    long long best_distance = LLONG_MAX;
    long long best_p = -1;

    for (auto& interval : free_intervals) {
        long long a = interval.first;
        long long b = interval.second;

        long long d1 = abs(s - a);
        long long d2 = abs(s - b);

        long long current_min;
        long long current_p;

        if (d1 < d2) {
            current_min = d1;
            current_p = a;
        } else if (d2 < d1) {
            current_min = d2;
            current_p = b;
        } else {
            current_min = d1;
            current_p = min(a, b);
        }

        if (current_min < best_distance) {
            best_distance = current_min;
            best_p = current_p;
        } else if (current_min == best_distance) {
            if (current_p < best_p) {
                best_p = current_p;
            }
        }
    }

    cout << best_p << endl;
}