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

#define ll long long

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    ll n, m, s;
    cin >> n >> m >> s;
    vector<pair<ll, ll>> p (m);
    for (int i = 0; i < m; i++) {
        cin >> p[i].first >> p[i].second;
    }
    sort(p.begin(), p.end());
    vector<pair<ll, ll>> z = {p[0]};
    for (int i = 1; i < m; i++) {
        if (z[z.size()-1].second+1 == p[i].first) {
            z[z.size()-1].second = p[i].second;
        }
        else {
            z.push_back(p[i]);
        }
    }
    m = z.size();
    pair<ll, ll> w = {1e18, 1e18};
    for (int i = 0; i < m; i++) {
        if (z[i].first <= s && s <= z[i].second) {
            if (z[i].first != 1) {
                w = {abs(s-(z[i].first-1)), z[i].first-1};
            }
            if (z[i].second != n) {
                w = min(w, {abs(s-(z[i].second+1)), z[i].second+1});
            }
        }
    }
    cout << w.second << '\n';
}