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#include <algorithm>
#include <bitset>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <deque>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

#define JOIN_(X, Y) X##Y
#define JOIN(X, Y) JOIN_(X, Y)
#define TMP JOIN(tmp, __LINE__)
#define PB push_back
#define SZ(x) int((x).size())
#define REP(i, n) for (int i = 0, TMP = (n); i < TMP; ++i)
#define FOR(i, a, b) for (int i = (a), TMP = (b); i <= TMP; ++i)
#define FORD(i, a, b) for (int i = (a), TMP = (b); i >= TMP; --i)

#ifdef DEBUG
#define DEB(x) (cerr << x)
#else
#define DEB(x)
#endif

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef unsigned int uint;

const int INF = 1e9 + 9;

vector<pll> segments;

void inline one() {
    ll n;
    int m;
    ll s;
    cin >> n >> m >> s;
    REP(i, m) {
        ll a, b;
        cin >> a >> b;
        segments.emplace_back(a, b);
    }
    segments.emplace_back(0, 0);
    segments.emplace_back(n + 1, n + 1);
    sort(segments.begin(), segments.end());
    vector<ll> candidates;
    // ll last = -1;
    FOR(i, 1, SZ(segments) - 2) {
        ll last = segments[i - 1].second;
        ll next = segments[i + 1].first;
        const auto &[a, b] = segments[i];
        if (a - 1 > last) {
            candidates.PB(a - 1);
        }
        if (b + 1 < next) {
            candidates.PB(b + 1);
        }
    }
    ll dist = static_cast<ll>(1e15);
    ll best = -1;
    for (auto cand : candidates) {
        ll temp_dist = abs(cand - s);
        if (temp_dist < dist) {
            best = cand;
            dist = temp_dist;
        }
    }
    cout << best << "\n";
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    // int z; cin >> z; while(z--)
    one();
}