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#include <bits/stdc++.h>
#include <climits>
using namespace std;

#define ll long long
#define pb push_back
#define F first
#define S second
#define pii pair<int,int>
#define vi vector<int>
#define vpii vector<pii>

#define loop(i,n) sloop(0,i,n)
#define sloop(s, i, n) for(ll i=(s);i<(n);i++)
#define rloop(i,n) rsloop(0,i,n)
#define rsloop(s,i,n) for(ll i=(n);i-->(s);)

#define all(v) (v).begin(),(v).end()

#ifdef DEBUG
#define DBG cout << __LINE__ << endl;
#else 
#define DBG
#endif 

//int xses[8] = {-1,1,0,0,-1,1,1,-1};
//int yses[8] = {0,0,-1,1,-1,1,-1,1};

#define int ll

void solve()
{
	int n,m,s;
	cin >> n >> m >> s;

	vpii v(m);
	loop(i,m)cin >> v[i].F >> v[i].S;
	sort(all(v));

	int id;
	loop(i,m)if(v[i].F<=s&&v[i].S>=s){id=i;break;}

	int l=id,r=id;

	int res1=INT_MAX,res2=INT_MAX;
	while(l>0)
	{
		if(v[l-1].S!=v[l].F-1){res1=v[l].F-1;break;}
		l--;
	}
	if(res1==INT_MAX)res1=v[0].F-1;
	
	while(r<m-1)
	{
		if(v[r+1].F!=v[r].S+1){res2=v[r].S+1;break;}
		r++;
	}
	if(res2==INT_MAX)res2=v[m-1].S+1;

	if(res1<1){cout<<res2;return;}
	if(res2>n){cout<<res1;return;}

	if(s-res1>res2-s)res1=res2;
	cout<<res1;
}

signed main()
{
	cin.tie(0);
	ios_base::sync_with_stdio(0);

	int t=1;

	//cin >> t;

	while(t--)
		solve();

	return 0;
}