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#include <bits/stdc++.h>
//#include <cassert>

const int inf = 2e9;
const long long ill = 4e18;
const long long mod = 998244353;
const long double eps = 1e-6;

#define pii pair<int, int>
#define tui tuple<int, int, ll>
typedef long long ll;
typedef long double ld;

using namespace std;

void solve() {
	for (int file = 1; file <=1; file++) {
		/*string fn = to_string(file);
		ifstream cin(fn+".in");*/
		ll n, m, s;
		cin >> n >> m >> s;
		vector<pair<ll, ll>> a(m);
		for (ll i = 0; i < m; i++)
			cin >> a[i].first >> a[i].second;
		ll before = -1, after = -1;
		sort(a.begin(), a.end());
		for (ll i = 0; i < m; i++) {
			if (a[i].first <= s - 1 && s - 1 <= a[i].second)
				before = i;
			if (a[i].first <= s + 1 && s + 1 <= a[i].second)
				after = i;
		}
		ll res = -ill;
		if (before == -1 && s!=1)
			res = s - 1;
		else if (after == -1 && s!=n)
			res = s + 1;
		else {
			vector<ll> gol;
			for (int i = 0; i < m; i++) {
				if (!(!i && a[i].first == 1 || i && a[i].first - 1 == a[i - 1].second))
					gol.push_back(a[i].first - 1);
				if (!(i == m - 1 && a[i].second == n || i != m - 1 && a[i].second + 1 == a[i + 1].first))
					gol.push_back(a[i].second + 1);
			}
			for (ll k : gol)
				if (abs(k - s) < abs(res - s))
					res = k;
		}
		/*ifstream ansin(fn + ".out");
		ll ans;
		ansin >> ans;*/
		cout << res << '\n';
		/*if (ans != res)
			cout << "ERROR at test " << file << ". answer:" << ans << '\n';*/
		
	}
	
}

signed main() {
	ios_base::sync_with_stdio(0);
	int t = 1;
	//cin >> t;
	while (t--)
		solve();


}