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#include <bits/stdc++.h>
 
using namespace std;
 
#define endl '\n'
#define L long long
#define MP make_pair
#define REP(i, n) for(int i = 0; i < n; ++i)
#define REPR(i, n) for(int i = n - 1; i >= 0; --i)
#define FOR(i, a, b) for(int i = a; i < b; ++i)
#define FORR(i, a, b) for(int i = b - 1; i >= a; --i)
#define EB emplace_back
#define ST first
#define ND second
#define S size
#define RS resize
 
template<class T> using P = pair<T, T>;
template<class T> using V = vector<T>;

L abss(L a) {
    return a >= 0 ? a : -a;
}
 
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

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

    V<P<L>> p(m);
    REP(i, m) {
        cin >> p[i].ST >> p[i].ND;
    }

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

    V<P<L>> r(1, p[0]);
    FOR(i, 1, m) {
        if (p[i].ST == r.back().ND + 1) {
            r.back().ND = p[i].ND;
        } else {
            r.emplace_back(p[i]);
        }
    }

    L res = 3LL * n;
    for (const auto& [a, b] : r) {
        if (a > 1 && abss(a - 1LL - s) < abss(res - s)) {
            res = a - 1LL;
        }
        if (b < n && abss(b + 1LL - s) < abss(res - s)) {
            res = b + 1LL;
        }
    }
    cout << res << '\n';
}

// g++ -std=c++20 -Wall -Wextra -Wshadow -Wconversion -D_GLIBCXX_DEBUG szk.cpp -o szk