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#include <bits/stdc++.h>
typedef long long ll;
#define nd second 
#define st first
using namespace std;

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    ll n, m, s; cin >> n >> m >> s;
    vector<pair<ll, ll>> seg(m);
    for (int i = 0; i < m; i++) {
        cin >> seg[i].st >> seg[i].nd;
    }   
    ll b = 0;
    ll l = -1, r = -1;
    bool c = false;
    sort(seg.begin(), seg.end());
    seg.push_back({n+1, 1e18});
    for (auto se: seg) {
        if (!c) {
            if (b < se.st-1) {
                l = se.st-1;
            }
            b = se.nd;
        }
        if (se.st <= s && s <= se.nd) {
            c = true;
        }
        if (c) {
            if (se.st == r) {
                r = -1;
            }
            if (r != -1) break;
            r = se.nd+1;
        }
    }
    if (l == -1) l = -1e18;
    if (r == -1) r = 1e18;
    if (s-l <= r-s) {
        cout << l << '\n';
    }
    else cout << r << '\n';
}