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#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define f first
#define s second
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    ll N, P, S, ans, r=9999999999999;
    
    cin >> N >> P >> S;
    vector<pair<ll, ll>> vp={{0, 0}};
    
    while (P--){
        ll a, b;
        cin >> a >> b;
        if (a>b) swap(a, b);
        vp.push_back({a, b});
    }
    vp.push_back({N+1, N+1});
    sort(vp.begin(), vp.end());
    
    for (int i=1; i<vp.size(); i++){
       // cout << endl;
       // cout << vp[i].f << " " << vp[i].s << endl;
        ll p=vp[i-1].s+1, k=vp[i].f-1;
       // cout << p << " " << k << endl;
        if (p>k) continue;
        if (S>k && abs(S-k)<r){
            r=abs(S-k);
            ans=k;
        }
        if (S<k && abs(S-p)<r){
            r=abs(S-p);
            ans=p;
        }
    }
    cout << ans;
    return 0;
}