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#include <bits/stdc++.h>
#define FOR(i, a, b) for(int i = a; i <= b; ++i)
#define RFOR(i, a, b) for(int i = a; i >= b; --i)
#define in insert
#define pb push_back
#define f first
#define s second
#define ll long long
#define ull unsigned long long
#define V vector
#define S set
#define eb emplace_back
#define P pair<long long, long long>
#define MS multiset
#define BS bitset

using namespace std;

void solve() {
    ll n, m, r;
    cin >> n >> m >> r;

    vector<P> pr(m);
    for (int i = 0; i < m; i++) {
        cin >> pr[i].first >> pr[i].second;
    }

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

    ll res = LLONG_MAX, wyn = -1;

    if (pr[0].first > 1) {
        ll kand = pr[0].first - 1;
        if (abs(r - kand) < res) {
            res = abs(r - kand);
            wyn = kand;
        }
    }

    FOR(i, 1, m - 1) {
        if (pr[i - 1].second + 1 < pr[i].first) {
            ll kand1 = pr[i - 1].second + 1;
            ll kand2 = pr[i].first - 1;

            if (abs(r - kand1) < res) {
                res = abs(r - kand1);
                wyn = kand1;
            }
            if (abs(r - kand2) < res) {
                res = abs(r - kand2);
                wyn = kand2;
            }
        }
    }

    if (pr[m - 1].second < n) {
        ll kand = pr[m - 1].second + 1;
        if (abs(r - kand) < res) {
            res = abs(r - kand);
            wyn = kand;
        }
    }

    cout << wyn << "\n";
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    solve();
}