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

#define pb push_back
typedef long long ll;

struct interval {
	ll l, r;

	bool operator < (const interval i) const {
		return l < i.l;
	}
};

int main() {
	ios_base::sync_with_stdio(false); cin.tie(NULL);

	ll n, s; int m;
	cin >> n >> m >> s;

	vector <interval> inter = {{0, 0}, {n+1ll, n+1ll}};
	for(int i = 0; i < m; ++i) {
		ll l, r;
		cin >> l >> r;
		inter.pb({l, r});
	}

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

	ll dist = n, p;
	for(int i = 1; i <= m; ++i) {
		ll cand = inter[i].l - 1ll;
		if(cand != inter[i - 1].r && abs(s - cand) < dist) {
			dist = abs(s - cand);
			p = cand;
		}
		cand = inter[i].r + 1ll;
		if(cand != inter[i + 1].l && abs(s - cand) < dist) {
			dist = abs(s - cand);
			p = cand;
		}
	}
	cout << p << "\n";

	return 0;
}