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

ll n, m, s;
vector<pair<ll, ll>> seg, merged_seg;

int main () {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	
	cin >> n >> m >> s;
	
	for (int i = 0; i < m; i++) {
		ll l, r;
		cin >> l >> r;
		seg.push_back({l, r});
	}
	
	sort(seg.begin(), seg.end());
	
	
	for (int i = 0; i < m; i++) {
		ll l = seg[i].first, r = seg[i].second;
		while (i + 1 < m && r + 1 == seg[i + 1].first) {
			r = seg[i + 1].second;
			i++;
		}
		merged_seg.push_back({l, r});
	}
	
	ll ans = 0;
	for (auto ms : merged_seg)
		if (ms.first <= s && s <= ms.second) {
			if (ms.first - 1 >= 1)
				ans = ms.first - 1;
			if (ms.second + 1 <= n && (ans == 0 || ms.second + 1 - s < s - ans))
				ans = ms.second + 1;
			break;
		}
			
	cout << ans;
}