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

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

    vector<pair<long long, long long>> segm(m);
    for (int i = 0; i < m; i++) {
        cin >> segm[i].first >> segm[i].second;
    }
    segm.push_back({0, 0});
    segm.push_back({n + 1, n + 1});
    sort(segm.begin(), segm.end());

    long long dist = LLONG_MAX;
    long long ans = -1;

    for (int i = 1; i < segm.size(); i++) {
        long long l = segm[i - 1].second + 1, r = segm[i].first - 1;
        if (l <= r) {
            if (s < l && abs(s - l) < dist) {
                dist = abs(s - l);
                ans = l;
            } else if (abs(s - r) < dist) {
                dist = abs(s - r);
                ans = r;
            }
        }
    }
    cout << ans << "\n";
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    solve();
}