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#include<bits/stdc++.h>

#define ll long long

using namespace std;

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    vector<pair<ll, ll> > V, W;
    ll n, s, a, b;
    int m;
    cin>>n>>m>>s;
    for (int i = 0; i < m; ++i) {
        cin>>a>>b;
        V.push_back({a, b});
    }

    sort(V.begin(), V.end());

    W.push_back(V[0]);

    pair<ll, ll> p;

    for (int i = 1; i < m; ++i) {
        if (W.back().second + 1 == V[i].first) {
            W.back().second = V[i].second;
        } else {
            W.push_back(V[i]);
        }
        
        if (W.back().first <= s && W.back().second >= s) {
            p = W.back();
        }
    }

    ll l = -1e13, r = 1e14;
    if (p.first - 1 > 0) l = p.first - 1;
    if (p.second + 1 <= n) r = p.second + 1;
    if (abs(s - l) <= abs(s - r)) {
        cout << l <<'\n';
    } else cout << r << '\n';
}