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#include<bits/stdc++.h>
using namespace std;
using LL=long long;
#define FOR(i,l,r)for(int i=(l);i<=(r);++i)
#define REP(i,n)FOR(i,0,(n)-1)
#define ssize(x)int(x.size())
#ifdef DEBUG
auto operator<<(auto&o,auto x)->decltype(x.end(),o);
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto&operator<<(auto&o,tuple<auto,auto,auto>t){return o<<"("<<get<0>(t)<<", "<<get<1>(t)<<", "<<get<2>(t)<<")";}
auto&operator<<(auto&o,tuple<auto,auto,auto,auto>t){return o<<"("<<get<0>(t)<<", "<<get<1>(t)<<", "<<get<2>(t)<<", "<<get<3>(t)<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif

int main() {
	cin.tie(0)->sync_with_stdio(0);

	LL n, s;
	int m;
	cin >> n >> m >> s;
	vector<pair<LL, LL>> segments(m);
	for (auto& [l, r] : segments) {
		cin >> l >> r;
	}
	auto occupied = [&](LL x) {
		for (auto [l, r] : segments) {
			if (l <= x and x <= r)
				return true;
		}
		return false;
	};
	pair<LL, LL> best = {1e18, 1e18};
	auto consider = [&](LL x) {
		if (occupied(x) or x < 1 or x > n)
			return;
		best = min(best, pair(abs(x - s), x));
	};
	FOR(i, -1, 1)
		consider(s + i);
	for (auto [l, r] : segments) {
		consider(l - 1);
		consider(r + 1);
	}
	cout << best.second << '\n';
}