#include <bits/stdc++.h>

using namespace std;
pair<long long,long long> tab[1009];
long long ind,wyn1,wyn2,wyn;
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
   long long n,m,s;
   cin>>n>>m>>s;
   for(int i=0;i<m;i++){
    cin>>tab[i].first>>tab[i].second;
   }
   sort(tab,tab+m);
   for(int i=0;i<m;i++){
   // cout<<tab[i].first<<" "<<tab[i].second<<endl;
   }
   for(int i=0;i<m;i++){
        if(tab[i].first<=s && tab[i].second>=s){
                ind=i;
                break;
        }
   }
   //cout<<ind;
   for(int i=ind;i>=0;i--){
        if(tab[i].first-1!=tab[i-1].second && tab[i].first-1>0){
            wyn1=tab[i].first-1;
            break;
        }
   }
   for(int i=ind;i<n-1;i++){
        if(tab[i].second+1!=tab[i+1].first && tab[i].second+1<=n){
            wyn2=tab[i].second+1;
            break;
        }
   }
  // cout<<wyn1<<wyn2;
   if(wyn1==0){
    cout<<wyn2;
    return 0;
   }
   if(wyn2==0){
    cout<<wyn1;
    return 0;
   }
  // cout<<wyn1<<" "<<wyn2;
   if(abs(s-wyn2)< abs(s-wyn1)){
        cout<<wyn2;
        return 0;
   }
   if(abs(s-wyn2)>= abs(s-wyn1)){
        cout<<wyn1;
        return 0;

   }
    return 0;
}