1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
#include<bits/stdc++.h>
using namespace std;
#ifdef DEBUG
auto&operator <<(auto& o, pair<auto, auto> p) {return o<<"{"<<p.first<<", "<<p.second<<"}";}
auto operator <<(auto& o, auto x)->decltype(x.end(), o) {o<<"{"; for(auto v : x) o<<v<<", "; return o<<"}";}
#define debug(X...) cerr<<"["#X"]: ", [](auto...$) {((cerr<<$<<"; "),...)<<endl;}(X)
#else 
#define debug(...){}
#endif
#define int long long
const int INF = 1e18+7;
#define mp(x, y) make_pair(x, y)
#define fi first
#define se second
#define eb emplace_back
int32_t main()
{
	cin.tie(0)->sync_with_stdio(0);
	int n, m, s;
	cin>>n>>m>>s;
	vector<pair<int, int> > segs;
	while(m--)
	{
		int l, r;
		cin>>l>>r;
		segs.eb(l, r);
	}
	sort(segs.begin(), segs.end());
	vector<pair<int, int> > full;
	for(auto it = segs.begin(); next(it) != segs.end();++it)
	{
		if(it->se + 1 == next(it)->fi)
			next(it)->fi = it->fi;
		else
			full.eb(*it);
	}
	full.eb(segs.back());
	debug(full);
	auto it = upper_bound(full.begin(), full.end(), mp(s, INF));
	it--;
	int a = (it->fi-1 != 0 ? it->fi-1 : INF),
	b = (it->se+1 != n+1 ? it->se+1 : INF);
	if(abs(a-s) <= abs(b-s))
		cout<<a;
	else
		cout<<b;
}