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#include <bits/stdc++.h>
using namespace std;
#define fwd(i, a, n) for (int i = (a); i < (n); i++)
#define rep(i, n)    fwd(i, 0, n)
#define all(X)       X.begin(), X.end()
#define sz(X)        int(size(X))
#define pb           push_back
#define eb           emplace_back
#define st           first
#define nd           second
using pii = pair<int, int>;
using vi = vector<int>;
using ll = long long;
using ld = long double;
#ifdef LOC
auto SS = signal(6, [](int) {
	*(int *)0 = 0;
});
#	define DTP(x, y)                                      \
		auto operator<<(auto &o, auto a)->decltype(y, o) { \
			o << "(";                                      \
			x;                                             \
			return o << ")";                               \
		}
DTP(o << a.st << ", " << a.nd, a.nd);
DTP(for (auto i : a) o << i << ", ", all(a));
void dump(auto... x) {
	((cerr << x << ", "), ...) << '\n';
}
#	define deb(x...) cerr << setw(4) << __LINE__ << ":[" #x "]: ", dump(x)
#else
#	define deb(...) 0
#endif

void sol() {
	ll n, s;
	int m;
	cin >> n >> m >> s;
	vector<pair<ll, ll> > ranges(m);
	rep(i, m) cin >> ranges[i].st >> ranges[i].nd;
	ranges.push_back({0, 0});
	ranges.push_back({n + 1, n + 1});
	sort(all(ranges));
	ll left = 0, right = n + 1;
	for (int i = 1; i < sz(ranges) - 1; i++) {
		if (ranges[i].st - 1 > ranges[i - 1].nd && ranges[i].st - 1 < s)
			left = max(left, ranges[i].st - 1);
		if (ranges[i].nd + 1 < ranges[i + 1].st && ranges[i].nd + 1 > s)
			right = min(right, ranges[i].nd + 1);
	}
	pair<ll, ll> ans = {n, 0};
	if (left != 0)
		ans = min(ans, {s - left, left});
	if (right != n + 1)
		ans = min(ans, {right - s, right});
	cout << ans.nd << '\n';
}

int32_t main() {
	cin.tie(0)->sync_with_stdio(0);
	cout << fixed << setprecision(10);
	sol();
#ifdef LOCF
	cout.flush();
	cerr << "- - - - - - - - -\n";
	(void)!system(
		"grep VmPeak /proc/$PPID/status | sed s/....kB/\' MB\'/1 >&2"); // 4x.kB
																		// ....kB
#endif
}