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#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;


int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //random_start();
    ll n,s;
    int m;
    cin >> n >> m >> s;
    set<pll> segs;
    rep(i,m)
    {
        ll l,r;
        cin >> l >> r;
        segs.insert({l,r});
    }
    pll ans = {1e17,1e17};
    ll cur = s;
    while(true)
    {
        auto it = segs.lower_bound({cur,1e16});
        if(it == segs.begin()) break;
        it--;
        if(cur < (*it).ff || cur > (*it).ss) break;
        cur = (*it).ff-1;
       // cout << cur << " c1\n";
    }
    if(cur >= 1 && cur <= n)
    ans = min(ans,{abs(s-cur),cur});
    cur = s;
    while(true)
    {
        auto it = segs.lower_bound({cur,1e16});
        if(it == segs.begin()) break;
        it--;
        if(cur < (*it).ff || cur > (*it).ss) break;
        cur = (*it).ss+1;
        //cout << cur << " c2\n";
    }
    if(cur >= 1 && cur <= n)
    ans = min(ans,{abs(s-cur),cur});
    cout << ans.ss << "\n";
}