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// clang-format off
#include <bits/stdc++.h>

using namespace std;

#define ALL(x) (x).begin(), (x).end()

template<class C> void mini(C &a5, C b5) { a5 = min(a5, b5); }
template<class C> void maxi(C &a5, C b5) { a5 = max(a5, b5); }

#ifdef LOCAL
const bool debug = true;
#else
const bool debug = false;
#define cerr if (true) {} else cout
#endif
// clang-format on

#define int long long
#define double long double

const int INF = 1e18;
const int mod = 1e9 + 7;

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n, m, s;
    cin >> n >> m >> s;

    set<int> bag;
    vector<int> candidates;
    for (int i = 0; i < m; i++) {
        int l, r;
        cin >> l >> r;
        candidates.push_back(l - 1);
        candidates.push_back(r + 1);
        bag.insert(l);
        bag.insert(r);
    }

    pair<int, int> res = {INF, INF};
    for (int x : candidates) {
        if (bag.find(x) != bag.end()) continue;
        if (x < 1 || x > n) continue;
        mini(res, {abs(s - x), x});
    }
    cout << res.second << '\n';
    
    return 0;
}/*

*/