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#define make_pair mp
#define emplace_back pb
#include <bits/stdc++.h>
using namespace std;
mt19937 mt_rand(time(0));
const int M = 1e3 + 5;
long long n, s;
int m;
vector<pair<long long, long long>> in;
bool cmp(pair<long long, long long> a, pair<long long, long long> b) {
	return a.first <= b.first;
}
int main()
{
	scanf("%lld %d %lld", &n, &m, &s);
	while(m--) {
		long long a, b;
		scanf("%lld %lld", &a, &b);
		in.pb(mp(a, b));
	}
	sort(in.begin(), in.end(), cmp);
	int num = 0;
	while(s > in[num].second) num++;
	int prev = num, next = num;
	while(prev != 0 && in[prev-1].second == in[prev].first - 1) prev--;
	while(next != in.size() - 1 && in[next+1].first == in[next].second + 1) next++;
	long long ans = 1e12 + 5;
	if(in[prev].first != 1) ans = s - in[prev].first + 1;
	if(in[next].second != n) ans = min(ans, in[next].second + 1 - s);
	if(in[prev].first != 1 && ans == s - in[prev].first + 1) printf("%lld", in[prev].first - 1);
	else printf("%lld", in[next].second + 1);
	return 0;
}