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#include <bits/stdc++.h>
using namespace std;
#define int long long
#define st first
#define nd second

constexpr int maxn = 1e6 + 7;
int z, n, m, s, res, poz, poc, id;
pair<int, int> pary[maxn], p[maxn];


int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m >> s;
    for(int i = 1; i <= m; i++){
        cin >> pary[i].st >> pary[i].nd;
    }
    sort(pary + 1, pary + m + 1);
    poc = pary[1].st;
    for(int i = 2; i <= m; i++){
        if(pary[i - 1].nd + 1 == pary[i].st){
        }
        else{
            p[++id] = {poc, pary[i - 1].nd};
            poc = pary[i].st;
        }
    }
    if(p[id].st != poc) p[++id] = {poc, pary[m].nd};
    sort(p + 1, p + id + 1);
    // for(int i = 1; i <= id; i++){
    //     cout << p[i].st << " " << p[i].nd << " ";
    // }
    // cout << '\n';
    res = LLONG_MAX;
    for(int i = 1; i <= id; i++){
        if(p[i].st == 1){
            if(abs(s - p[i].nd) < res){
                poz = p[i].nd + 1;
                res = abs(s - p[i].nd);
            }
            continue;
        }
        if(p[i].nd == n){
            if(abs(s - p[i].st) < res){
                poz = p[i].st - 1;
                res = abs(s - p[i].st);
            }
            continue;
        }
        if(abs(s - p[i].st) == abs(s - p[i].nd) && res > abs(s - p[i].st)){
            res = abs(s - p[i].st);
            poz = p[i].st - 1;
        }
        else if(res > min(abs(s - p[i].st), abs(s - p[i].nd))){
            if(abs(s - p[i].st) < abs(s - p[i].nd))
                poz = p[i].st - 1;
            else
                poz = p[i].nd + 1;
            res = min(abs(s - p[i].st), abs(s - p[i].nd));
        }
    }
    cout << poz << '\n';
    
}