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#include <bits/stdc++.h>

using namespace std;

#define st first
#define nd second
#define pb push_back
#define rep(i,a,b) for(int i = a; i <= b; i++)
#define irep(i,a,b) for(int i = a; i >= b; i--)
typedef long long ll;
typedef long double ld;
//typedef __int128 int128;
typedef vector<int> vi;
typedef pair<int,int> pi; 
typedef pair<double,double> pd;
typedef pair<ll,ll> pl;

const ll INF = 1'000'000'000'000'000'007;
vector<pl> v;

int main(){

    ios::sync_with_stdio(0);
    cin.tie(0);

    ll n,m,s; cin >> n >> m >> s;
    rep(i,1,m){
        ll l,r; cin >> l >> r; v.pb({l,r});
    }
    sort(v.begin(),v.end());
    ll ans = INF; ll ind = 0;
    rep(i,0,m-1){
        ll l = v[i].st; ll r = v[i].nd;
        if((i == 0 && l != 1) || (i != 0 && v[i-1].nd != l-1))
            if(abs(s-(l-1)) < ans){
                ans = abs(s-(l-1));
                ind = l-1;
            }
        if((i == m-1 && r != n) || (i != m-1 && v[i+1].st != r+1))
            if(abs(s-(r+1)) < ans){
                ans = abs(s-(r+1));
                ind = r+1;
            }
    }
    cout << ind;

    return 0;
}

//g++ -O3 -static -Wall .cpp -std=c++17