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#include "bits/stdc++.h"
using namespace std;
#define rep(i,a,b) for(int i=(a); i<(b); ++i)
#define all(x) x.begin(),x.end()
#define sz(x) int(x.size())
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vi> vvi;

const ll oo = 1e18;

int main(){
    cin.tie(NULL),cin.sync_with_stdio(false);
    
    ll n,m,s; cin >> n >> m >> s;

    vector<ll> pts(m*2), tries(m*2);
    rep(i,0,m){
        cin >> pts[i*2] >> pts[i*2+1];
        ++pts[i*2+1];
        tries[i*2] = pts[i*2]-1;
        tries[i*2+1] = pts[i*2+1];
    }

    ll ans = 1e18;
    ll at = 0;

    sort(all(pts));
    for (auto x : tries){
        if (x >= 1 and x <= n){
            int cnt = upper_bound(all(pts),x)-begin(pts);
            if (!(cnt&1)){
                if (abs(s-x) < ans or (abs(s-x) == ans and x < at)){
                    ans = abs(s-x);
                    at = x;
                }
            }
        }
    }

    cout << at << '\n';
}