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#include <bits/stdc++.h>
using namespace std;

#ifdef GGDEBUG
#define dbg printf
#else
#define dbg // dbg
#endif

using ll = long long;

struct Interval {
    ll left, right;
    bool operator<(const Interval &other) const { return left < other.left; }
};

ll n, m, s;
vector<Interval> intervals;
vector<Interval> free_intervals;

int main() {
    scanf("%lld %lld %lld", &n, &m, &s);

    for (int i = 0; i < m; ++i) {
        ll l, r;
        scanf("%lld %lld", &l, &r);
        intervals.push_back({l, r});
    }

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

    ll best_dist = n + 1;
    ll res = -1;

    if (intervals[0].left > 1) {
        free_intervals.push_back({1, intervals[0].left - 1});
    }
    if (intervals[m - 1].right < n) {
        free_intervals.push_back({intervals[m - 1].right + 1, n});
    }

    for (int i = 1; i < m; ++i) {
        if (intervals[i - 1].right + 1 <= intervals[i].left - 1) {
            free_intervals.push_back(
                {intervals[i - 1].right + 1, intervals[i].left - 1});
        }
    }

    for (auto interval : free_intervals) {
        dbg("free interval: [%lld, %lld]\n", interval.left, interval.right);
    }

    for (auto interval : free_intervals) {
        ll left = interval.left;
        ll right = interval.right;

        ll now;

        if (s < left) {
            now = left;
        } else if (s > right) {
            now = right;
        }

        ll dist = abs(now - s);
        if (dist < best_dist) {
            best_dist = dist;
            res = now;
        }
        if (dist == best_dist && now < res) {
            best_dist = dist;
            res = now;
        }
    }
    cout << res << endl;

    return 0;
}