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#include <bits/stdc++.h>
#define fi first
#define se second

typedef long long ll;

using namespace std;

ll cal(ll a, ll b)
{
	ll ans = a - b;
	if (ans < 0)
		return -ans;
	return ans;
}

int main()
{
	cin.tie(0); cout.tie(0); ios_base::sync_with_stdio(false);

	vector<pair<ll, ll>> li;
	ll n, m, s, l, r;
	cin >> n >> m >> s;

	for (int i = 0; i < m; ++i)
	{
		cin >> l >> r;
		li.push_back({ l, r });
	}

	li.push_back({ 0, 0 });
	//li.push_back({ s, s });
	li.push_back({ n + 1, n + 1 });
	sort(li.begin(), li.end());

	ll ans = (LLONG_MAX - 1) / 3, resp = 0;

	for (int i = 1; i < li.size() - 1; ++i)
	{
		if (li[i - 1].se + 1 < li[i].fi && ans > cal(li[i].fi - 1, s))
		{
			ans = cal(li[i].fi - 1, s);
			resp = li[i].fi - 1;
		}

		if (li[i].se + 1 < li[i + 1].fi && ans > cal(li[i].se + 1, s))
		{
			ans = cal(li[i].se + 1, s);
			resp = li[i].se + 1;
		}

		/*if (li[i - 1].se <= s && s <= li[i].fi)
		{
			if (li[i - 1].se < s - 1)
			{
				ans = 1;
				resp = s - 1;
			}

			if (s + 1 < li[i].fi && ans != 1)
			{
				ans = 1;
				resp = s + 1;
			}
		}*/
	}

	cout << resp << '\n';

	return 0;
}