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#include <bits/stdc++.h>
using namespace std;
#define ll long long
const ll maxm = 1007;
ll n,m,s;
pair<ll, ll> rans[maxm];


int main() {
    cin >> n >> m >> s;
    for ( ll i = 0; i<m; i++ ) {
        cin >> rans[i].first >> rans[i].second;
    }
    sort(rans, rans + m);
    // for (int i = 0; i<m; i++) {
    //     cout << rans[i].first << ", " << rans[i].second << "\n";
    // }
    ll fi=-1;
    vector<pair<ll,ll> > freerans;
    if (rans[0].first > 1) {
        freerans.push_back(make_pair(1, rans[0].first-1));
    }
    for (ll i = 0; i<m; i++) {
        ll donleft = 0;
        if (i!=0) {
            donleft = rans[i].first - rans[i-1].second - 1;
        }
        if (donleft > 0) {
            // cout << donleft << " - left \n";
            freerans.push_back(make_pair(rans[i-1].second+1, rans[i].first-1));
        }
    }
    if (rans[m-1].second < n) {
        freerans.push_back(make_pair(rans[m-1].second+1, n));
    }

    ll value = 2*n;
    ll buildingNumber = -1;
    for (auto fr : freerans) {
        // cout << fr.first << ", " << fr.second << "\n";
        ll leftDistance = abs(fr.first - s);
        ll rightDistance = abs(fr.second - s);
        if (leftDistance < value) {
            buildingNumber = fr.first;
            value = leftDistance;
        }

        if (rightDistance < value) {
            buildingNumber = fr.second;
            value = rightDistance;
        }
    }
    cout << buildingNumber << "\n";
}