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

#define int long long
#define ii pair<int,int>
#define iii tuple<int,int,int>
#define fi first
#define se second
#define endl '\n'

#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define lb lower_bound
#define ub upper_bound

#define rep(x,start,end) for(int x=(start)-((start)>(end));x!=(end)-((start)>(end));((start)<(end)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());

int n,m,s;
vector<ii> v;

signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin.exceptions(ios::badbit | ios::failbit);
	
	cin>>n>>m>>s;
	rep(x,0,m){
		int a,b; cin>>a>>b;
		v.pub({a,b});
	}
	
	v.pub({0,0});
	v.pub({n+1,n+1});
	
	sort(all(v));
	
	int ans=1e18;
	int best=-1;
	rep(x,0,sz(v)-1) if (v[x].se+1<v[x+1].fi){
		int l=v[x].se+1,r=v[x+1].fi-1;
		
		if (l<=s && s<=r){
			ans=0;
			best=s;
		}
		if (ans>abs(l-s)){
			ans=abs(l-s);
			best=l;
		}
		if (ans>abs(r-s)){
			ans=abs(r-s);
			best=r;
		}
	}
	
	cout<<best<<endl;
}