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#include <bits/stdc++.h>


using namespace std;
#define ll long long
#define ld long double
#define all(a) (a).begin(), (a).end()
#define allr(a) (a).rbegin(), (a).rend()
#define F first
#define S second
#define pb push_back
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
/*
#ifndef ONLINE_JUDGE
    #include <cpp-dump.hpp>
#endif
*/
constexpr ll mod = 1e9+7;

ll power(ll a, ll b){
    ll res = 1;
    while(b){
        if(b&1) res = res * a % mod;
        a = a * a % mod;
        b >>= 1;
    }
    return res;
}

/*
ll fact[300001];
ll C(ll n, ll k){
    if(k < 0 || k > n) return 0;
    return fact[n] * power(fact[k], mod-2) % mod * power(fact[n-k], mod-2) % mod;
}
*/

void dzik77() {

    ll n,m,s; cin >> n >> m >> s;
    ll ans = 1e18;
    ll best = 1e18;
    vector<pll> a(m);
    for (int i = 0; i < m; i++){
        ll l,r; cin >> l >> r;
        a[i] = {l,r};
    }
    sort(all(a));
    ll cl = a[0].F, cr = a[0].S;
    for (int i = 0; i < m; i++){    
        if(a[i].F <= cr+1){
            cr = max(cr, a[i].S);
        }
        else{
            if(cl-1 >= 1 && abs(cl-1-s) < best){
                best = abs(cl-1-s);
                ans = cl - 1;
            }
            if(cr+1 <= n && abs(cr+1-s) < best){
                best = abs(cr+1-s);
                ans = cr + 1;
            }
            cl = a[i].F;
            cr = a[i].S;
        }
    }
    if(cl-1 >= 1 && abs(cl-1-s) < best){
        best = abs(cl-1-s);
        ans = cl - 1;
    }
    if(cr+1 <= n && abs(cr+1-s) < best){
        best = abs(cr+1-s);
        ans = cr + 1;
    }
    cout << ans << '\n';

}

int32_t main()
{

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

    /*
    fact[0] = 1;
    for (int i = 1; i < 300001; i++){
        fact[i] = fact[i-1] * i % mod;
    }
    */

    int t = 1;
    //cin >> t;
    while(t--)
		dzik77();

    return 0;
}